At last, a bit of an academic perspective about this personality issue I have and why I seem to [so easily] accept more fluid boundaries about my sexuality (and why some others absolutely can NOT accept it). It seems there is a scale... one of many, attempting to describe sexuality, ever since Kinsey decided to start studying sex objectively (did anyone see the movie?). Anyway, this scale to which I'm referring is what's called "sociosexuality". It describes the comfort level and acceptance of this notion we know of as "casual sex". The two extremes of this scale are "restricted" and "unrestricted", defining the two polarities of individual values, limitations, and factors which go into the decisions that people make when entering into sexual situations.
When I read this article (HTML or PDF), it hit me like a big breath of relief. As though momentarily everything wasn't about ethics or morality anymore, and I could just breathe natural air. Real, natural air. There are a LOT of details in this article, and if you're not familiar with academic scientific studies, it may be difficult to get through. Even still, I HIGHLY suggest reading it, even if you just skip all the paragraphs with statistical mumbo-jumbo. Even just reading the introduction is very illuminating.
The article describes various characteristics about people who have certain tendencies. Briefly for example: comfort with uncommitted casual sex, premarital sex, multiple sexual partners, sex with or without romantic love, extramarital sex, etc.
It's funny, I've always tried to stay away from "labels" or "identifications", but on the two accounts of sexual orientation and sociosexual orientation, I've actually been relieved to feel some form of identification. Discussions of leading an ethical and good life surely will follow, as they always do. But for earthly centering, I feel balanced and whole with these perspectives on who I am and why I choose to do the things I do.
If you're interested, here are some further discussions about sociosexuality:
1) a study on gender, and the differences of how an unrestricted sociosexual orientation affects men & women (HTML or PDF)
2) "A 48-Nation Study of Sex, Culture, and Strategies of Human Mating" (HTML or PDF)