So whether you've just been going through a dry spell recently or are more seriously concerned that you haven't got down to it in months (or years), we have spoken to two experts to find out what to do at each stage.
It isn't yet a problem, but it has been a while since we had sex.
Do flirt with each other.
This might seem like an alien concept after having seen your partner leave their dirty underwear all over the house for ten years, but flirting will help you stop loosing the spark in the first place.
Sex expert Tracey Cox told The Huffington Post UK: "Are you snorting with derision at this advice? Listen, I was with you! That was until I studied a really happy couple I know and realised they've never stopped flirting. There it was, the extended, adoring eye gaze we all do at the start. Standing really close, giving full attention, kisses on the forehead, always touching each other."
Don't go for subtle hints, be obvious.
If you are worried that your partner no longer takes notice of you when you're trying to initiate sex, maybe they aren't noticing rather than choosing to ignore you? Don't be afraid to ask for what you want.
Cox says: "What seems abundantly clear to you, may be misinterpreted by them – which is disastrous. It is all well and good to toss a sultry look as you head up the stairs to bed, but unless you're sporting a Victoria's Secret push-up bar, thong and a garter belt at the time, sultry could be mistaken for sulky...Have an agreed private code that says - sex tonight?"
Do see sex as something to keep track of.
This might not seem like a particularly romantic way to view your marriage, but Cox is adamant that this mentality helps no matter what stage you are at, she says: "You need to make regular deposits to keep the balance healthy.
"If you've just come back from a pleasant little shagathon in the Greek Islands, the balance is nicely topped up. Saying no the night you get back isn't going to cause problems. But if you haven't made a deposit for six weeks or more, that balance is getting dangerously low."
Do not feel bad about faking it till you make it.
We all know that faking orgasms is no way to a satisfying sex life, but getting in the mood isn't always easy and we should be prepared to psyche ourselves up sometimes when you'd rather just watch TV, as things will begin to slide in that department.
Cox says: "It's childish to expect both of you to always be gagging for it simultaneously. And numerous studies show lots of us warm up once we get going."
It has become a problem and is starting to damage our marriage.
Don't see intimacy as limited to sex.
Ok, so all couples have waves when it comes to sex, sometimes you are having more, sometimes you are having less. And right now you're definitely having less. But don't think that just because you aren't having sex, all intimacy is off the cards.
Jenny Porter, Director of Client Services for Marriage Care and relationship therapist, told HuffPost UK that you can create intimacy in other ways that could help get back to sex: "Maintain intimacy in other ways by holding hands, sharing kisses, and cuddling. Staying in the habit of practicing physical affection will make it more likely for you to want to have sex."
Don't be afraid to compromise your expectations.
It can be difficult, if you feel like the physical part of your relationship is on the way out, not to just demand more in order to compensate for this, but Cox says that sometimes we need to compromise on what we are expecting from our partner: "The high desire person decides on the least amount of sex per fortnight they'd be happy with.
"The low desire person decides on the most often they'd be willing to do it. Then you choose the number in the middle of the two. Making it fortnightly allows for life interfering with the commitment. Make it monthly and you forget what you promised. It's a good starting point."
Do vow to do your part, not just sit back and wait.
When you are feeling unloved (and not particularly unattractive) it can be tempting to always wait for your parter to initiate sex - perhaps we set this test because we want to see they still fancy us - but why ever you do it, you have to accept that you are 50% of the problem.
Cox explains: "Talk about what you would like to do in the sex sessions. Say what you most like and least like, though play nicely and focus more on the positives than negatives. How could you improve things that aren't working? Be specific about what you need and want. Talk about when you did have great sex. What did you both do differently back then?"
We haven't had sex in such a long time, it feels like it will never happen again.
Do keep open communication.
Both of you know what is going on and both of you are aware of the void in the bedroom, so keeping quiet about it isn't going to help anyone. According to Cox, as many as 40% of men said the fact they weren't sleeping with their wife was because they were furious with her.
And Porter agrees, saying: "Couples who are angry with one another are more likely to avoid sex. Keep your sex life alive by learning better ways to work through your problems and being open, honest, and respectful."
Do see your partner as a friend, as well as a spouse.
If you are struggling to see eye to eye, especially between the sheets, go back to the other reasons why you fell in love in the first place. Porter says: "Keep your friendship strong. Make a set time at least once a week where you go out together and enjoy each other's company. Whether it means going for dinner or a walk in the park, take this time to enjoy face-to-face connection."
Do show your partner that you still care.
We've all been there, you don't need to tell your partner you care anymore because they know. They telepathically know. Or so we tell ourselves.
Even in the most stable of relationships, everyone wants to be reminded of how much they mean to someone else, Porter says: "Show your partner you care. This could be as simple as making them a cup of tea in the morning or thanking them for something they've done."