Am I wrong to feel rejected when he doesn't want to be intimate?

you should feel that way. there has to be a reason why he no longer wants to be intimate with you, and based on how we guys act, generally that means if he is not getting something from you he is getting something from somebody. honestly there can be no other explanation. he is a guy. he has a gf. he would want sex. by not wanting it, he is in effect rejecting you as a gf, making you a friend instead.