Very sticky situation, that intimacy business.
I remember that country song in the last decade or two that started out: "They said 'your love life's in trouble' in a magazine I read, 'When the one you love is hanging off of his side of the bed'..... "
I thought that was so much bs. But for me I can look back and know that it's always been true. When getting physical with someone is no longer attractive to me because of hurts, abuses, disrespect, and dishonesty, I know there's not much I can do to get that feeling back. Sex isn't something I dole out as a reward. It's a feeling that comes from inside myself that expresses itself in the fun and joy and play of the physical act.
And when the feelings inside myself are mistrustful, angry, hurt, and I've lost respect for someone, I'm not in the tiniest bit interested in that physical act.
At. All.
If you plan on staying in the relationship and working this out, then it might help to visit a counselor together and see what small steps you can do to regain trust and intimacy.
But if the thought of doing that elicits a gut reaction of "No way,dude", then you may want to do yourself -- and him -- a favor and start the process of separating. Sex is far too important to most men (and many women) to expect to go through life never sharing it again, regardless of whether they are at fault or not. Anger and hurt will continue to build no matter how much explaining and justifying you try to do.
Just my two cents' In you I don't see selfishness.......you're just not willing to force/pretend/fake feelings that you don't have inside you.