Lisa can't remember the last time she had sex with her husband and doesn't know if it matters.

I’ve been married for 15 years to a great man. I love him. Everyone loves him. Whenever anyone has a problem, friends or family, they call Pat and he’ll always go out of his way. We both work and have three kids under 14 and life is busy. But I can’t complain about Pat helping out around the house. A lot of my friends whine about their husbands having a domestic blind spot when it comes to meals and laundry and all that other boring household stuff, but Pat does his share. We’re great talkers too. We don’t have secrets and we go on long walks with the dog and talk for ages. Our friends always comment that we are such a great couple. And I think we are. I think I’m really lucky. I can’t wait to get home at night and see Pat. I just can’t remember the last time we had sex. We used to have lots of it when we first got together. The last time could have been four months ago, or six. I’m not sure. And I’m not sure if I miss it. I’m not sure if Pat does either. – Lisa, 42.

You meet someone. Fall in love. Have as much sex as possible. It’s exciting, adventurous. Headaches don’t exist. Early nights aren’t so necessary.

Then, somewhere, somehow along the way, the sex stops.

It goes days, weeks, months… Then even years since you last had sex. Wanted sex, even.

Sex therapist Matty Silver says this is the story of countless couples.

“When I ask them when they last had sex, they can’t remember and it’s not unusual for them to tell me they haven’t had sex for at least six months or sometimes several years,” Silver wrote in The Sydney Morning Herald. “But they did have satisfying sex lives in the past. They can remember it being so much fun in the early years of their relationship.”

There is a definition for a “sexless relationship” – it’s having sex less than 10 times in one year. For some, this might be a normal, mutual-satisfying, situation, but Silver says that is rare. Usually at least one person, if not both, in the couple want to have sex more frequently.

That figure shocks Lisa (who doesn’t want to use her real name). She says her and Pat are still very affectionate with each other. It’s just the sex that they are missing.

Well we’re in a sexless marriage then. That sounds shocking: sexless. I didn’t think it was like that, I just thought we didn’t have sex very much. There’s no reason either. I mean there’s plenty of people who have kids and have much more sex than we have so I can’t blame the kids for our sex life. I really can’t think of when it all kind of got so slow. I don’t think we meant it to happen. But now I’m thinking maybe there is a reason we’re not having sex.  – Lisa, 42.

“Not all sexless relationships are doomed. And that’s okay, as long as both people are happy not to have sex any more. However, in my experience that – unfortunately – is very rare.”

A marriage without sex can be fixed, Silver says. They key is to address the problem early, bearing in mind a lack of sex might be a symbol of a bigger, deeper problem within the relationship.

“When couples don’t sort out these problems, sooner or later resentment will surface and intimacy and sex will go on the back-burner,” she wrote. “Problems should be discussed, otherwise couples will grow apart, leaving both frustrated, resentful and angry.”

Listening to your partner, as well as talking about your own needs and concerns, is integral to this.

“I believe relationships can improve if people listen to each other more instead of telling each other what’s wrong,” Silver wrote. “Rather than complaining about what your partner doesn’t do, tell him or her exactly what they can do to turn you on. When you talk about sex, focus on the positive.”

To make sex work, it’s important to let go of certain myths. For example, “sex should be spontaneous”, “it should be easy”, “it should be natural”. These ideas dangerous. They put additional pressure on the couple. They are also incorrect.

Lisa isn’t sure whether her and Pat have a problem, whether it’s a stage, or whether it’s a way of life now.

“I never thought I would be in a relationship that was defined as sexless,” she says. “It’s something I’ve always imagined might happen to other couples, but not us.”