Lack of empathy.. Really hurts
I had to have my cat put down a couple years ago. We brought the kids in to say goodbye. I was in tears and there was no reaction from him at all. At the time he wasn't officially off the wagon but I was definitely in the way. Two months later he was getting drunk and not hiding it from me any more.
They just can't see past the bottle.. Even if he was a non alcoholic and just didn't love me anymore.. He would have felt something. I just got 'shark eyes', ya know.