I read a book many years ago that's now dog-eared from getting me through two divorces and a major breakup. It's called "Uncoupling: Turning Points in Intimate Relationships" (by Diane Vaughan). She is a sociologist, and she interviewed both halves of dozens of couples who were going through or had gone through breakups (including married couples, people living together in committed relationships, gay and straight). It doesn't have to do with addiction/alcoholism specifically.
What she found was that in almost all situations, one person is the "Initiator" of the breakup--the one who first wants out and the other is the "Partner" who may not have a clue for a long time what's in the other's mind. What she also found is that most breakups follow a typical pattern where people go through the motions of "trying to make it work" with each of them, though, having different agendas (possibly agendas they aren't even aware of). The point of "trying" from the Initiator's viewpoint is to convince themselves and the Partner that this can't possibly work. The point of "trying" on the Partner's part is to save the relationship.
In all three cases I was the "Initiator" but it was very enlightening to me to see how the dynamics really did seem to be almost universal, and it rang very true for me.
So it may be that he is just going through the motions to satisfy both of you that this won't work out. It sure doesn't seem like his heart is in the relationship. He may not even be sure what it is he really wants, but if I were you I think I would proceed with your plan.
Wish I had a therapist to suggest--I think it's a good idea for you to talk to somebody. A reality check can be very useful.