He loved her she didn't feel the same way back. When he seen her with another guy is destroyed him he felt unworthy. The betrayal was on a whole other level. He didn't fight because she never belong to him when he moved on she'd come back. It really messed with his mind. She told him he was a good friend then got into a relationship. She claimed to love him now that she's married he wanted to be friends now he gets why he can't be connected to couples. The frustration and complication.