Is it possible that I'm slutty because I'm...a good, kind person? Absolutely, say scientists at Villanova and Rutgers Universities studying the interpersonal "meaning" of promiscuity. Charting personality traits against the number of sexual partners, Patrick and Charlotte Markey, who headed up the study, found that those who get around the most are either warm/affectionate or cold/distant, with few falling in between, a statistic that holds true for both men and women. According to Patrick:

Some people might sleep with multiple partners not because they are selfish but because they view sexual activity as an extremely warm activity and want to share it with others.

Eh, I still say I do it because it's just fun. And that would place me in the cold/distant category, which means, if you're like me, we "avoid serious relationships and the attendant risk of rejection," or we "just want to have as much fun as possible with no regard for the feelings of others." Yeah, that second one, I think. But really, it doesn't matter to me if I'm warm or cold, just as long as my partners are hot. (Ba dum bum.)

Promiscuity: Spread The Love [Psychology Today]