Rose you are (to my mind) very hard on yourself, you say you are maybe thin skinned but who wouldn't be feeling hurt and disoriented by his behaviour?

I think you are also being triggered to an earlier unhappy time as his current behaviour is reminding you of how he was and made you feel back when he was drinking heavily and being abusive towards you. That is another dimension you are coping with in addition to his current illness.

It's not surprising you see similarities as both alcohol and dementia affect the inhibitions and reasoning - that is most likely what you are seeing in him now. How he is behaving towards you now sounds quite typical of dementia.