'This is fixable': What really helps save a relationship

What couples therapists want you to know about trying to save a relationship that's going downhill.

If you're in an unhappy relationship, you may suffer from heartache – literally.

Vicious arguments can result in poor sleep and even heart pain and muscle pain. They can make everyone in the family, including children, more vulnerable to physical and mental health problems.

A happy relationship can boost your health and even your lifespan. An unhappy one can have the opposite effect, raising your risk of an earlier death by chipping away at your health.

In fact, poor-quality close relationships are considered a health risk factor equal to or greater than smoking or lack of exercise. And then, of course, there's the metaphorical heartache: the pain of love unravelling.

So how do you turn an unhappy relationship into a happy one? And is that even possible?