The Spark Doesn't Always Fade. Sara Tang on Keeping Desire Alive in Long-Term Relationships

A lot of the couples I see describe the same slow slide. The early months were electric, then life filled up with work, kids and logistics, and one day they realise that sex has become something that happens on birthdays and at Christmas. Most of them assume that means something is broken, either in the relationship or in them. So I sat down with Sara Tang to ask the question I get asked most: how do you keep the spark alive in a long-term relationship?

Sara is a sexologist and sex coach in Hong Kong, someone I've learned a great deal from, and the host of the Better in Bed podcast, which she started before Covid after growing up in a conservative, religious household where none of these conversations were allowed. She wanted to build the conversations she wished she'd had access to. The roles were reversed for this one, and I was the one asking the questions. Here's what she walked me through.

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You can't really just move straight from work mode all the way to sexy mode.

Sara Tang, sexologist and sex coach

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Two misconceptions that quietly kill desire

Sara sees the same two misconceptions again and again. The first is that the spark should sustain itself. In the early days of a relationship desire feels effortless, you can't stop thinking about each other, you're constantly texting, and it's easy to assume that this will carry on indefinitely without any sustained effort or attention. The second is that most people don't fully understand how sexual desire actually works, and the two misconceptions feed each other.

The science points to two main types of desire. Spontaneous desire is the instant, “I'm so horny” kind. You walk into a room, there's a flirty look, and you're fired up with hardly any warm-up. It's common early in a relationship. Responsive desire is the kind that builds gradually, in response to something, usually physical touch or emotional closeness. It's more common in longer relationships, and Sara is clear that both are perfectly healthy and valid.

Responsive desire is not the same as no desire

Here is where couples get into trouble. When spontaneous desire fades and responsive desire takes over, a lot of people conclude that they have no desire left, that the spark is gone and it's time to move on. Sara calls that a real shame, because responsive desire can be every bit as strong as spontaneous desire if it's cultivated in the right way.

That cultivation starts with what Sara calls sexual accelerators and brakes. Couples who have leaned on spontaneous desire often have no idea what theirs are, because everything used to turn them on, so everything was an accelerator. Once the honeymoon period passes, the brakes show up: stress, kids, menopause, or just a hard day at work. Sara runs this as an exercise with the couples she works with, and the aim is for each partner to know what switches them on, what shuts them down, and to share it. If that sounds like a conversation you'd rather not have alone, it's a big part of what happens in sexual wellness therapy for couples.

Nothing is wrong with you: what the brain scans show

I told Sara what I'd felt in my own relationships. When the spontaneous desire went away, I assumed I just didn't like the person anymore, or that something must be wrong with me or with the relationship. Things that never used to bother me started to, and I found my own brakes. Her first response was to take a step back, because asking how to fix it assumes something is broken, and she doesn't think it is.

She pointed to Dr. Helen Fisher's TED talk, “Your Brain in Love.” Fisher scanned people at different stages of a relationship. At around three months, the dopamine centres, the brain's chemistry for pleasure, reward and motivation, light up like fire. This is the state Fisher calls limerence. At three years, the dopamine centres are still active but less intense, and other regions have started to light up, the ones linked to oxytocin and vasopressin, the neurochemicals of companionship and bonding. Sara's reading is that this is a good thing. It points to more emotional regulation, more stability and a closer sense of bonding. You're not losing the relationship, you're gaining things the honeymoon phase never had.

The part that surprised me is how much novelty matters. Sara agreed that sex often feels more exciting on holiday or in a new place, and that anything new, from role play to toys, can reactivate those dopamine centres. We're all on what she called the hedonic treadmill, where the brain just gets used to things, so keeping the spark alive takes consistent effort to bring in something new.

The FIRE framework

Sara uses a simple framework with couples who want to keep the spark alive. It's called FIRE, and each letter stands for something.

F is for fresh experiences, the novelty that reactivates the dopamine centres. It can be anything: a HYROX challenge, a dance class, a new gallery, a staycation, or sex in a new space. I is for intimate connection. Long-term couples fall into routine and then complacency, and they begin to live parallel lives. When you break down how much dedicated time a couple with kids actually has for each other, it's often tiny, and most of it is spent coordinating schedules and paying bills. Her easy fix is twenty minutes at the end of the day, or a weekly date night, with phones away and a moratorium on talking about the kids. Ask about your partner's dreams, goals and fears, and update your understanding of their inner world.

Rituals, and why you can't go straight from work mode to sexy mode

R is for rituals of connection. A peck on the cheek on the way out the door is affection, and Sara likes it, but a ritual in her sense is a consistent, repeated practice where you take time to be intimate together. Where to start depends on the couple. If there is no touch at all, she starts small with a kiss on the cheek. If there is already affection, she moves it one step further, to something that isn't the kiss you'd give your aunt or your mum.

She is also a big fan of transition rituals. It's hard to switch on desire for each other straight after a busy day, and many couples have only three modes, work mode, parent mode and sex mode, with nothing in between. A glass of wine together and a few questions about each other's day is a simple bridge. She described a couple where the husband worked late and came home stressed. His wife would initiate with no build-up at all, it felt awkward, she felt rejected, and it turned into a cycle in which neither knew what was going on.

Part of the answer was responsive initiation. Initiating doesn't have to be an instant “take your clothes off.” It can be gentle, no-pressure touch, and the initiating partner has to be willing to hear no without sulking, withdrawing or feeling rejected, because a nice make-out session or a naked cuddle is a good outcome in its own right. The responsive partner, for their part, needs to be willing to entertain the idea that they might get into it once they're given the right stimulation. Sara compared it to going to the gym. You don't feel like going, but once your shoes are on and you're warming up, you get into the right headspace, and afterwards you're glad you went.

Erotic charge and the 24 hour foreplay protocol

E is for erotic charge, and Sara reaches for it most with couples who feel like roommates, couples who are close friends with plenty of love and affection but whose relationship has become very platonic. Erotic charge is the sexual energy you build before and between whatever happens in the bedroom. She suggests thinking of desire as a phone battery rather than a light switch. You can keep charging it through the day until you're ready.

One of her tools for this is the 24 hour foreplay protocol. If a couple already has a weekly date night, they get a task: for the 24 hours before it, try to turn each other on as much as possible. Flirty texts, teasing, the things that came naturally in the early days. It's a game, and as I said to her, the worst that can happen is nothing, which is where the couple already is. The point is that foreplay doesn't only happen in the bedroom.

When desire is mismatched

I asked what she says to couples whose desire is far apart, where one wants it all the time and the other hardly at all. Her starting point is values. Sex is like money, in that its meaning varies enormously from person to person. For some it's sacred and only with someone they love and feel cherished by. For others it's more of a physical release. Getting those meanings out in the open comes first.

From there, she looks for common goals and shifts the focus from quantity to quality. If one partner wants sex five times a week and the other once a month, any point in between feels like a huge compromise for both of them. Moving the conversation to the quality of the sexual connection often gets couples unstuck. She is also clear that sex and the relationship are tangled together, so it's very hard to work on the sex when you don't really like each other as a couple.

Every couple is different, so she starts with a personalised assessment and uses evidence-based, practical frameworks, because the couples she sees are usually fighting for time and headspace. Intimacy tends to fall to the bottom of the to-do list, below the kids, ageing parents and work stress. For couples who haven't had sex in months or years, she doesn't say “just have sex.” She gives them small baby steps to warm the relationship up first. If you're wondering whether that describes you, I've written about the signs a couple needs counselling even when they think they don't.

Educate, explore, communicate

When I asked for practical tips on getting better in bed, Sara gave me three steps. Educate yourself, because there is so much misinformation and shame around sex, and a podcast, a book or a few videos can be very empowering. Explore, because you need to know what feels good for you before you can unlock what feels good for someone else, and great sex with yourself helps unlock great sex with other people. Then communicate, which takes the confidence, and sometimes the vulnerability, to tell a partner what you need.

If that last step feels impossible, she says the work starts earlier, with the belief that's limiting you. Often people don't know what they want, or they don't feel worthy of expressing it. Once that has shifted, keep the first conversation small. She suggests three columns, what I like, what I don't like, and what I'm curious to try. It can turn into a deeper conversation or stay a quick check-in. If you're too scared to even do that, go back to the belief system first. For anyone who recognises themselves in that, Valentina Tudose's take on self-worth and relationship problems and Shawn Griffin's on what men get wrong about sexual shame cover the same ground from other angles.

Sara also offered a useful test of emotional safety. If you and your partner can talk about other awkward topics, money for example, you are probably in a good position to start a conversation about sex. If the relationship doesn't have that safety, the conversation will be testing it, and she recommends professional support, a coach or counsellor, to help you through it. Often people who fear this conversation have tried it before, and it went badly, or a past partner said something hurtful. I see the same with men who come to me with erectile difficulties that have no physical cause: a bad experience, something said, and a belief about themselves that took root and kept repeating. Sex is one of the most vulnerable experiences we have, and it's easy to feel judged for saying what you actually like.

My own takeaway from the conversation is that a fading spark is not a verdict on your relationship. It's usually a change in the type of desire, plus a few brakes that nobody has named yet. The couples who stay connected aren't the ones who never lose the honeymoon feeling. They're the ones who stop assuming it should be effortless and start building it on purpose.

Sara Tang is a sexologist and sex coach based in Hong Kong. You can find her at sarasense.com and on Instagram at @hellosarasense, and listen to the Better in Bed podcast, where a new season is due out soon.

If you and your partner have drifted into roommate mode, or you're struggling to bring up what you want, that's something we work on every week. Book a free consultation with us and we'll take it one small step at a time.