Do yourself a favor and stop contacting him. Also, find yourself some friends. This guy is not "interested in building good relationships." Time will ease all your pain over being rejected by him.

His marriage ended in divorce. His 20 year relationship with recent GF was going nowhere. He was hitting on you, despite cohabiting with someone else. No, this is not a guy who forms good relationships with anyone. Don't take it personal. You're looking for something from him that he doesn't have to give.