You've already been doing everything you can for this relationship. You've put in so much, but unfortunately, your boyfriend has stopped putting in effort. He's making the choice not to reciprocate your love and caring. Those "jokes" he's making-- I would take them at face value. I think he's subconsciously trying to tell you something. And he's being very cruel and callous about it. Not to mention his distant behavior. This is not how a loving, dedicated partner acts.