I think you have to raise any behaviour you find upsetting, see what his response is and take it from there. (And I agree with advice above about getting yourself into a good mental place to do that)
My DH was rather horrific for a period. He pretty much had a breakdown after work problems collided with an ill child plus severe money issue. At that time his behaviour was often unacceptable. This happened very soon after we married and I thought maybe I had married someone who seemed nice but turned into a monster after the vows.
However he went to counselling both for the behaviour and his feelings. He has addressed a lot of issues from his own childhood (his own father is, erm, interesting) and he has become a 98% reasonable man (we're all annoying in some way, aren't we?). The stresses I mention have all disappeared too so base stress is much lower.
I have discussed with my DH that I am worried if we go through stress again he will become hideous again. He thinks he will become stressed and grumpy and maybe less fun, but does not believe he will go back to being verbally aggressive and passive aggressive in turns, because he genuinely didn't know what he was doing, now he sees it, doesn't want to be like that and stops himself. He says he does occasionally get the knee jerk response of avoiding a question but he can intercept himself.
What I am saying, in a long-winded way, is I believe you can't tell without giving someone chance to explain and maybe change (this is with non-violent and not too extreme behaviour only - if he was saying 'you're a fat cow, I hate you' then there is no excuse for that). But if they don't actually change, you have to give up at some point and walk away. I would have walked (I had a deadline and was preparing things just in case) but things are so different I am now staying put, because I am happy, it's been 18 months of improvement. I also had to change some things btw, less of it was down to me but I did have to take a look at some of my contributions.