Why Breakups Are Harder on Men

No doubt you've heard a lot about sex addiction lately, thanks to guys like Russell Brand and David Duchovny, but I believe that phenomenon is more likely a form of obsessive-compulsive disorder (which is a whole different story!). Love, on the other hand, is an addiction. Passion fades over time because the brain's reward system physically changes in the same way it does for a heroin addict: Its receptors for dopamine, a neurochemical that triggers euphoria, are altered, and in place of the rush, you feel more of a need. You must have your partner just to avoid feeling miserable. Even though being with him or her produces less pleasure than at the beginning, being without him or her produces a feeling of loss. Sigh.

When you're on the Pill, it can weaken his sex drive.

Here's the deal: Men can sense ovulation. Your man may not know he's sensing it, but he is more likely to unconsciously engage in what scientists call mate-guarding—interrogating you about where you're going, snooping through your purse, asking about your cute male coworker. His brain is telling him that now's the time you can make a baby, and that if there's any baby-making to be done, he's going to be the one to do it. Scientists are still trying to discover exactly how men pick up on this timing—it might be slight changes in your body shape (breasts become a little more symmetrical), color (skin lightens), or voice (it gets higher). Pheromones may also be involved; in one study, guys judged the scents of women near ovulation to be sexier. But the point is this: When you're on the Pill, you don't ovulate, so you miss out on this unconscious hotness boost. Scientists have found, for instance, that when strippers were ovulating, they made about $90 more per shift than at other times in their cycle—while strippers on the Pill never got the pay bump. Don't go throwing out your pack just yet: There are other factors to male libido, like not worrying about getting you pregnant!

When I first embarked on this journey with Larry, I was a little disturbed that a few chemicals in my head had so much influence over my life. But then I remembered some of my past shenanigans—yes, I'm talking about you, former Chicago Bears cheerleader—and I felt relieved to know there was a reason for my lack of reason. Besides, if we weren't wired this way, we'd never fall in love, and we wouldn't be driven to have sex, and there would never be any babies. Evolutionarily speaking, that's why all this chemistry exists. So what if it makes us go a little nuts sometimes? It's also the gift that delivers the greatest joys of life. So go ahead. Open it. There are happy surprises inside.

Brian Alexander is a former Glamour contributing editor. An award-winning journalist, he's also written several books.