He has a drinking problem
He has been a shite father to his children
His mental health problems have never been properly addressed or dealt with, yet are often rolled out as an excuse for his behaviour
To cut a long story short, my mum has been with her partner for around 10 years. He is fundamentally a 'nice guy' in that he is funny, generous, kind etc etc.
However, he drinks excessively. He has never (as far as I know) been abusive to my mum or done anything dangerous when drunk, but he has a habit of doing stupid things - falling over, breaking things, having silly arguments with people. Things that as a one of occurrence could be forgiven, but he is 56 years old and they happen far too often. The next morning he is always full of remorse and promises to cut down on his drinking blah blah blah, but he never does.
He has two children who are now in their late teens from his previous marriage, and both have gone 'off the rails'. Since he moved divorced their mother when they were young children, he has (in my opinion) done the bare minimum that is required of him (i.e. visits every other weekend, paid maintenance etc) I don't even know why this is relevant, but it definitely makes me think less of him. He also regularly blames his ex-wife for his childrens' behaviour - 'well if she controlled them better etc' - he doesn't acknowledge his own responsibility to them at all.
He has apparently been diagnosed with depression (I say apparently as I have only heard this from my mother, he has never spoken of it) His depression is regularly used by my mum to excuse his behaviour - he will snap at her about something trivial and then disappear out on a long dog walk for hours without saying anything to her and that will be 'because of his depression.' However, whenever I have asked her what steps he is taking to deal with his mental health, she very quickly dismisses the issue ('oh he's fine, he's been like it for years, he knows how to deal with it')
Anyway, I guess the point of all this is (and thank you if you are still reading) is that it's beginning to affect my relationship with my mum. I am beginning to dislike her partner more and more and it now means that I don't really enjoy spending time in their company, and I feel myself being agitated when my mum talks to me about him. The problem is, my mum was shit on rather spectacularly by my dad about 15 years ago and she got together with her now DP quite quickly after. Whenever I try to raise the issue of his behaviour, I just get 'well, he treats me a lot better than your father ever did' which is true, but she doesn't seem to get that that is not saying much and that it doesn't mean she has to tolerate his other shite behaviour. I'm not even suggesting that she does anything as dramatic as leaving him, but I just wish she had the confidence to realise that she doesn't have to accept or justify his behaviour and that it isn't ok.
I have a brother who feels exactly the same as me, but he is a lot less emotionally involved. He is very much of the 'she's an adult, let her get on with it' school of thought, but for me to think like that I would need to emotionally distance myself from my mum and I don't want to do that. She's my mum.
Sorry this is so long, I just need to get it out somewhere.