Couples who do chores together are happier, fight less and have better sex lives, according to new research.

Americans spend an average of 664 hours doing household work each year, and women spend about an hour more each day tidying up than men do.

Equal sharing of the burden of chores is becoming more common, however, and research suggests that as it does women are feeling less put upon and more in the mood.

What's more, sex therapist Dr Ian Kerner advises that doing housework together can make the chores go quicker, build communications with your partner and even turn make the dish-washing steamy.

Couples can improve their relationships and sex lives by doing chores together, research suggests

Juvenile as it may seem, fighting over housework was the primary cause of divorce for a full quarter of Americans, according to a survey published earlier this year.

And, apparently, who does the dishes is the biggest cause for quarrel for women.

Researchers from three universities broke down how more than 600 couples divvy up chores, and how satisfied they were in their relationships and sex lives.

Women who felt like they washed the lion's share of the dishes were more likely be unhappy with their partners.

When it comes to house work, we have come along way toward equality, and appear to be better for it.

Research on chore habits using data from the 1980s and 1990s actually suggested that couples who took more traditional household roles were happier, but a newer survey found that both partners are better off when the duties are split.

'A lot of today's relationships are sort of egalitarian and having a partner who helps out with chores is just about having a collaborative, egalitarian relationship, which is what many of expect,' says Dr Kerner.

But overall, who does the housework means a lot more to women than it does to men.

Division of at-home labor did not predict much about how men felt about their relationships, but having to spend more time at the kitchen sink seems to really put a damper on women's sex drives.

The survey did not ask women why dishes were such a sore subject for them, but a few factors may be at play.

Sloughing soggy half-eaten food off of plates and turning your fingers to prunes under running water can be nasty business.

Plus, dishes follow meal preparations - which many women also do - and doing both can feel like double-duty at the end of a long day.

'Women out there in the workforce resent coming home and doing a double-shift, and feel like [doing the dishes] is reverting to antiquated gender norms,' Kerner says.

What happens outside of the bedroom happens inside the bedroom. So if you feel resentful or like you're doing an unfair share of chores, it doesn't make you feel very sexual Dr Ian Kerner, sex therapist

When their male partners roll up their sleeves and do the dishes though, women feel more attended to and cared for, which in turn was linked to higher rates of overall relationship and intimacy satisfaction.

The study authors hinted that the general changes to gender roles that have been slowly occurring have helped to push along a more egalitarian home dynamic.

Now, in the majority of marriages - about 60 percent - both people work.

That change has upset the old dynamic of a 'woman's' work being in the home, while the man is at his job, meaning both people have the same amount of time to accomplish things around the house.

Better yet, couples can make chores themselves a more intimate, bonding activity by doing them together.

'Doing things with your partner - making life easier and eliminating stress by taking things off your to-do list - helps to cement your sense of partnership and attachment, so when you think about your partner your see them as someone who is ethical and considerate.'

A 2013 study found that women felt most like the division of labor was equal in their relationships when they did housework side-by-side with their partners.

Doing the household necessities together is the surest way to eliminate a nasty power dynamic that many couples fall into: one person drags their feet about chores, while the other nags.

That in itself can boost your chances of having a better time in the bedroom, says Dr Kerner.

'What happens outside of the bedroom happens inside the bedroom. So if you feel resentful or like you're doing an unfair share of chores, it doesn't make you feel very sexual,' he says.

Dr Kerner explains that this translates particularly clearly for women: 'As a woman approaches climax, parts of the female brain associated with stress and anxiety tend to dim and deactivate.

'But if you have a sink full of dirty dishes it's harder to get to that part of your brain to turn off,' and get the turned on portions of the brain to turn on, he says.

In fact, he thinks that doing the dishes - though it may be the most dreaded chore - is actually a simple opportunity for strengthening a relationship.

Women out there in the workforce resent coming home and doing a double-shift, and feel like [doing the dishes] is reverting to antiquated gender norms Dr Kerner

'Dish-washing is one [chore] that really fosters collaboration and communication with your partner,' he says.

It can even be a good starting place for some banter and flirtation.

'My wife sees me stacking the dishes in the dishwasher and says I'm doing it all wrong, and redoes it, but it's playful and engenders a little communication and maybe learning - I probably could be better at stacking dishes,' Dr Kerner says.

He says he's heard from clients that things can even get a little steamier around the dishwasher.

'Women say: "I bend over to put dishes in the dishwasher, and all of a sudden he's up behind me, grinding on me!"' Dr Kerner says.

But if doing housework in sync is still too much of a stressor, research shows that shelling out the money for a cleaning service is worth every penny.

A Harvard Business School study found that couples who paid for convenience services were more satisfied in their relationships, and felt like they got more quality time together rather than the necessary time spent on chores.

Of course, this only works for those who have more money than time to waste - and it's free to make mopping a 'fun' shared experience.

He says his clients complain that 'mainly, there's so much to do and no time for sex and by the time they get in bed they're exhausted.'

'They have no time for sex and complain that their life is sort of mundane and routine, full of chores and no fun or sexiness or eroticism in the relationship,' he adds.

So time is the issue to focus on, says Dr Kerner, and 'four hands instead of two are helpful to make chores go faster and seem less overwhelming.