He's a little boy who has been dropped on his head a few too many times and thus he isn't thinking straight and is going to end up in a mental institution for his insecurities and his constant bipolar mood swings that cause him to be a danger to himself and those around him. He is emotionally unstable, narcisistic, and a psychopath.
Do yourself a favor and just leave him alone because the sex won't be good, you will end up as screwed up as he is, and he might cause you to commit suicide. Also, he might kill you.
I will do my best to reply with an educated, humble and honest answer. Ultimately, it is up to you whether you want to listen to my advice or ignore it completely. Sometimes, my advice may be wrong; occasionally, it will be right. Regardless, I want to do my best to give people answers they are seeking.