First of all, welcome to MS Buster. You are right out of the gate asking some good questions. Personally I don't think its much of an issue who you choose to have sex with. There are all kinds of sex you can have with all kinds of people. Sex may be healthy and mutually pleasureable.
But if you are finding that the sex you're having causes you to feel dirty, wrong, and to hate yourself, theres probably something wrong there. There are lots of twisted messages about sex out there, and they don't all come from religion. Porn tells us that unless we have the bodies of Atlas and a firehose between our legs that we are sexual failures. Women tell us that we have to make good money, have hot bodies, stable lives, and know how to make them scream with pleasure.....when THEY feel like it.
How do you find your way to a healthy sexuality amid all the crap you've been fed? I don't think there's a simple answer. But I think it starts with changing certain beliefs about yourself. "I am dirty, ugly, stained, damaged goods, messed up, worthless, disgusting, and a peice of crap." (Did I miss anything?) Those are all things I've believed without question for years. I am working hard on cutting myself some slack, and taking a chance on believing something different about me. What have I got to lose? What have you got to lose?
Jude