Scientists know that women gravitate to men who have a different immune system from theirs.

Natural beauty really entices men. They will tell you this time and time again, and studies consistently prove it.

Your sweetheart calls you by another's name. His eyes linger too long on your best friend. He talks with excitement about a girl at work. And the fire catches. Jealousy - that sickening combination of possessiveness, suspicion, rage, and humiliation - can overtake your mind and threaten your very core as you contemplate your rival.

We still have community, but we don't seem to have local community. Even in a small town where you know your neighbors and your mother's down the street, they're not in arm's length.

Sometimes we fall in love with somebody who will probably never love us, for reasons having nothing to do with us but with their own mindset, their chemistry.

Neither gender is routinely more jealous - although women are more willing to work to win back a lover, while men tend to flaunt their money and status and are more likely to walk out to protect their self-esteem or save face.

There were real reasons that you were attracted to somebody originally. The brain doesn't pick willy-nilly. Unless you part ways hating each other for some reason, that mechanism could get triggered again. You can literally fall in love again.