If by 'what things should I be looking for' you mean in terms of whether he has learned to control his anger, I don't know how much of this applies to everyone and how much applies to me only. I can tell you how it was for me:
1. My outbursts were also infrequent, but like I mentioned previously, there was also the undercurrent. Let's say I ended up raising my voice and being aggressive and loud (and thereby threatening and intimidating) every 4 months. I realized at least that long would have to pass before I even got her attention and made her think it was possible I had changed.
2. From her side...I think it took between 6 months and a year for it to start to sink in for her that this was a real change and a new habit, and not just temporary damage control done out of a sense of panic on my side over possibly losing her.
3. After a year or so, my kids also started to remark that I seemed a lot calmer and less tense all the time, more easygoing like I used to be. Easier to approach and talk to. I think that made a difference for her.
4. I eventually, slowly started doing more special things for her and trying to be closer and more affectionate (without chastising her for not initiating) once I felt like she was a bit more open to that.
So that part has gotten better. The other problems in our marriage, some of which have been instigated by her behavior, remain unsolved by her choice.
At some point I had to step back from things, tell her I'll support her if she wants to make progress. And I had to just keep reminding myself, "Not my circus, not my monkeys."
