hi I'm just what the name implies, but your problem doesn't sound like any kind of mental illness. my thinking is that someone has hurt him very badly in his past. are you involved with his parents is he this could go along way back. maybe he really is broken up over he kids or its a left over from his ex'es treatment. maybe hes afraid of bonding while hes in the middle of bonding or he made up his mind that if he hurts himself now it wont hurt so much when you move on (his belief , I'm not saying you are.)do not contact his ex. its really hard to say,you really need to find a way to get him to open up. its right there in front of the two of you. with some people you just cant walk through the front door with,ya have to sneak around the side.i know everyone is telling you to go to counseling I'm not a big believer in it most people lie to their counselors