Secret of Sticking to partner REVEALED!

Researchers think they may have found a clue in oxytocin, a hormone released during sex and other intimate gestures like hugging or holding hands that's been proven to strengthen social bonds in other mammals.

They found that the hormone appears to boost men's attraction to their mate -- even when presented with pictures of other women. The findings are published in this week's issue of the Proceedings of the National Academy of Sciences.

In the study, 20 men who were in committed relationships for 28 months, on average, took whiffs of either oxytocin nasal spray or an inactive placebo spray. For the first test, the men looked at pictures of their partner, a woman they'd never met, or a house. The photos of the women were carefully matched so one wasn't more attractive than the other.