I'm kind of a newbie, so take heed with what I say!
Outside of talking about the A, does he bring up other topics? Do you feel like you are truly intimate with each other? Can you pretty much talk about everything else but the A?
If you are close, intimate and talking about your day, your friends, your families, your feelings, and other such stuff, then he might have closed the door on it and wants to focus on the future.
If you don't feel close, intimate, and don't share about your lives maybe he has closed the door on his feelings and thinks he is protecting himself from further pain. Maybe look at books and exercises how to build intimacy into your relationship. (Five love languages, Gottman, etc) Is in IC?