how good a friend is this guy bc that's a, (ummm, trying to think of a delicate way to say it when what i really want to say doesn't sound very nice) enabling, guilt trippy, crappy kind of thing to say.
is this friend trying to play god and be intermediary and think that you owe your ex some new consideration or that you need to be concerned about his feelings?
i'm feeling annoyed for you by this friends presumptuousness. i have pretty much stopped talking to people who didn't "get" it when i stopped lying about what life with AH was like. i don't begrudge them their opinions or lack of ability to get it, but nor do i feel compelled to spend time with people who i feel i need to explain or justify my behavior to.
i have friends who don't live with or haven't dealt with alcoholism who get it just fine and don't ask things like your friend did. maybe you could set a clear boundary with him that you don't wish to hear about your ex at all and then it just won't be a part of conversation?