REVEALED: This is what a 'normal' sex life actually looks like...

Traditionally, therapists say sex accounts for about a quarter of a couple's happiness in their relationship.

But new studies reveal all sorts of interesting – and contradictory - evidence to show just how much sex contributes to long-term satisfaction with a loved one. 

According to relationship expert James Preece, a so-called "normal" sex life isn't quite as exciting as you think, the Daily Mail reports. 

"When couples first get together there is initially an experimental phase," says James. "Sex is often and varied as we get to know each other. It's the time when we find out each other's tastes, desires, fantasies and sexual triggers. 

"However, as time goes by, life gets in the way and we settle into a more regular routine. This usually means far less sex than many people think - once or twice a week at most. 

"You might believe everyone is getting it on constantly but the reality is much different," he insists. 

"Even when we do have sex it's usually at the same time each week doing the same thing. This is usually because of different and longer working hours. Many people complain they are too tired for sex as it can sometimes seem like a chore. It's much easier to cuddle up in front of the TV than spring into action. 

"Libidos are rarely in sync and it's common for one of you to want it more and at different times to your partner. So if one person initiates it, the other might not be in the mood, which can cause problems. 

"Once children come into the equation this can often be considerably less too. 

"They demand much of your time and people don't feel at their sexiest. 

"A normal sex life is like slipping on a comfortable jumper rather than exploring a slinky dress. 

"It's whatever feels right for both of you and at a level you are both happy with. 

"Just make sure you allow time for it as sex is a very important part of a happy relationship."