I think I may of been sexually abused as a child

You will probably need to speak to a therapist in order to get to the root of your issues, particularly with what may be repressed memory. I am no therapist but if there was abuse, it's not a matter for just casual friendly (or anonymous Internet) advice -- it's a matter for a professional.

And no, it's not a pity party. Don't worry about that -- if it indeed happened, then it's something you've got to deal with. Nothing pitiful about that -- in fact, it's a strong position to deal with your past, whatever it might be.

As for your partner, I imagine it's a difficult subject for him to broach which is why he's silent on the matter (how do you know he was abused? Did he tell you that much at some point, or did you hear it from someone, or infer it?). Saying that you understand is, well, it's not productive and probably not the case. Even if you both had identical experiences, it doesn't necessarily mean a shared understanding or a shared reaction. It doesn't mean you can't be loving and a good listener. I think the sentence, "You can tell me anything, and I care about you and I will do my best not to judge." is one that should be said in any and every relationship, regardless of whether anyone's been abused. I'd say that, or a variation of it. If it leads to him opening up to you, fine. If not, that's also fine, too. You got the message out, that you're a safe person to talk to.

Now, as for the changes in your behavior, appearance, etc., I don't necessarily think it's self-destructive but recognize that, sometimes, we change ourselves for the sake of trying to please the people we care about. That's not, usually, such a great thing to do, over time. Losing your own identity in someone else is a recipe for eventual resentment. Be who you are - and you might not know the details of that, yet. But don't be who someone else thinks you should be.

I know he was abused because a friend of his told me very little details about it

Well, people don't always tell the truth/stretch the truth. But no matter. If he doesn't want to talk about it, well, you can't make him, yanno.

You think you were the victim of childhood sexual abuse? Apart from some vague feelings of resentment or anger against your parents and relatives, what makes you think you were abused as a child?

You may also have a case of 'tranference" from your BF's background. You seem very focused on him.

Some husbands get sympathy symptoms when wife gets pregnant, even experiencing morning sickness.

In any case, get some help from a counselor.

live in the present, not in the past, you learn by experience not by denying it, don't waste your life wondering about what "might" have happened because you are only gonna destroy your lives together. Loving each other and being comfortable together is all u need.

Whats transference

Your feelings are valid. Normally survivors attract other abusers as well as survivors of sexual abuse. It normally will run in the family. Have you spoke with your sibilings to see if this has happened to them? What about the rest of your family. It is time to break the silence, and talk. If it is happening in your family, it is worth opening your mouth and causing a ruckus. Its the only way to prevent these things from happening to our future children. No, you can't really bring up that you know about your boyfriends abuse as a child, but you can bring up your own memories as they come. Maybe in time he will share with you. If you have to question whether or not it happened, chances are it probably did.

P.S. I did my time in therapy for many years. Now, I am finally free. I lost a lot of family members along the way. That's ok.

Oh, and I believe you. If you have that sick feeling that something happened. There IS a reason. For whatever that reason is, I am truly sorry you are experiencing this.