“Oxytocin bonding” doesn’t only occur in flawed relationships though, sometimes it can emphasize feelings you have out of bed as well.

“Sometimes you just look at [your partner], and think, he makes me so happy. With [my boyfriend], it’s more like that after [sex]. It feels like a level of elation, but to a greater extreme—all I want to do is tell him how much I love him,” Tara* says.  

While we’d like to think that this post-coital love surge is simply how we feel, the truth is it may have more to do with the orgasm-induced rush of oxytocin.

Why is this happening?

Susan Kuchinskas, who writes a blog about oxytocin and has a book, Love Chemistry: How Oxytocin Lets us Trust, Love and Mate, due early in 2008, offers some insight:

“Oxytocin seems to have been ‘designed’ by nature to make a man and woman feel bonded after sex, so they would stay together and raise children,” she says. “Today, the physiology of men and women still plays out according to this pattern. But estrogen seems to increase the calming and bonding effects of oxytocin, while testosterone seems to mute them. That's why women tend to feel more attached after sex than men do.”

The website oxytocin.org sites a study that found oxytocin can also be released in response to intense emotions. In the study, women were asked to recall positive and negative relationship memories.

Most had only small increases or decreases in their oxytocin levels, but women whose levels rose significantly while remembering a positive relationship also reported having healthier relationships in general. Women whose levels fell dramatically while remembering a negative relationship also reported anxiety in their relationships. More research needs to be done, but this could indicate that oxytocin plays a part in whether we form healthy relationships or not.