Oh Lady bless your heart. I'm not sure how much help I can be, but I'll offer what thoughts I can.

In my experience here, most of the people I've read of who dissociate (particularly during sex, though not always) are doing so as a result of trauma. Dissociation is a sort of psychological defense employed by the brain to avoid the reliving of painful or traumatic memories. Wikipedia (not the most reliable source, I know, but it's all I have ) does mention it is possible for people to dissociate under intense "conflict or boredom," so trauma is, using Wikipedia's standard, not strictly necessary. Is there a point from when you first became sexually active in where you can pin down where things started to change? Additionally, while it might be hard to talk about, can you tell us a little more about why you feel guilty and ashamed, especially if that's been going on for a while? Your reasoning could help us.

How do you feel about your current BF? You told us how he feels about you, but not you about him (minus the sexual aspect, but my hunch is that the problem with him isn't sexual in nature but emotional). Additionally, how did you feel working as a dancer or model? Sorry to offer so many questions instead of answers, but I think with some additional information, I can offer you more.

One thing though that I can certainly tell you as of right now is that there is absolutely no need to be ashamed or guilty, and you are very far from the worst person in the world. Please, don't think either of those things about yourself. A "bad" person wouldn't be sitting here trying to begin the arduous task of self improvement, would they? You're human, just like the rest of us.

I hope, in time, I will be able to be of help to you. You're in my thoughts and prayers.

Hugs,
Harley