I agree with oliviab . Drawing such a hard line - seems like the damage is already done. He is not comprehending his role as a t. I get the sense that he is trying to stop you from finding out something shady about his role in the community - like he's a player or something. So even if he were no longer your t, you would not like having him in the community. It feels like, unless he can resolve this issue for himself, he can no longer be your t. Its not a you problem, its a him problem. He is being unethical.