Jason and Michelle have been together for seven years and have two children together. Picture: Channel 7.

Jason and Michelle have been together for seven years - they have four-year-old son and an eight-month old daughter - but they haven’t had sex in 17 months.

During an exercise with the show’s therapist Peter Charleston, Michelle watches a video of herself having an argument with Jason.

The fight covers all bases: She wants help with the kids, she thinks he works too much, he wants sex, she doesn’t want to have sex.

“Michelle, what if you tried to appeal to Jason by talking about something that he will listen to — something that’s important to him,” suggests Mr Charleston. “Think about it as a bargaining tool. What bargaining tool do you have?”

Michelle immediately blurts out, “sex”, and is told to use Jason’s desire for sex to her advantage.

But withholding or offering up sex to get what you want - be it a home cooked meal, an unpacked dishwasher, or actual human interaction - is not a great idea, says Matt Tilley, a clinical professional fellow from Curtin University’s Department of Sexology.

Jason and Michelle sit down and chat about their relationship on the Seven Year Switch.Source:Supplied

“I wouldn’t support a strategy of bargaining. I would look at the root cause of the dissatisfaction in the relationship to see how the lack of sex could be resolved,” Mr Tilley told news.com.au.

“The idea that anyone can just turn sex off and on for their partner when there may be a reduced or insufficient connection, is absolutely ludicrous.”

Many couples experience what sexologists call “desire discrepancy”. It’s unlikely for two people to have matched levels of sexual desire during their entire relationship.

“We have to figure out how each individual gets their needs met. The three options are: resolving it within the relationship, staying together but seeking sex elsewhere, or breaking up,” Mr Tilley said.

OK, so bargaining for sex isn’t a great idea. But can it work in other parts of your relationship?

Say the man wants to take his partner to the footy, and she wants to take him to dinner with friends. Both don’t want to go to either, but they make an agreement to stick it out at the other’s chosen event.

“The dangers of that being built into the foundation of a relationship is the power and control imbalance,” Mr Tilley said. “Both partners are likely to end up feeling manipulated.”

The couple say they haven’t had sex in 17 months.Source:Supplied

OK, so not a great idea. Back to sex. We all want to be having more of it, so how can you negotiate that with your partner?

“Sex is not necessarily something that we use transactionally,” Mr Tilley said. “Some people might, but typically that’s not how sex operates. I think that the age old ideas of improving communication and connection in a relationship are the way forward.”

Therapy can be a good way to help couples “move past the resentment and pain” and actually come up with practical solutions to their problems.

And finally, don’t expect to have mind-blowing sex each time you get between the sheets.

“In a highly sexualised world we often set ourselves unrealistic expectations about the kind of sex we’ll be having,” Mr Tilley said.

“We’re all chasing fireworks, we all want it to be amazing all the time, and that sets us up for disappointment. If it’s good 80 per cent of the time, that’s realistic.”

Seven Year Switch airs on Channel Seven on Tuesday at 9pm.