Hi op
The way I got around my ds being upset if his I hesitate to use the word Dad
Didn't turn up or was always late. I just didn't tell him, so it was a surprise if he did, and nothing different if he didn't.
It might help if you can adjust your out look and expectations of him and him as a so called Father.
Don't expect him to play ball, always have plan B and stick to it
Always expect the unexpected, he is no longer your friend or wants the best for you
The only person you can rely on is yourself, then you can't be let down, he will always only do what's best for him, remember he has to make this shit choice of his work, if it's failing then he will blame you.
Don't think for a second that everything's rosey in his garden, he's got to keep her happy as well, the mental stress he's going to have to expend to do this
Will be crippling him (also diddums)
Remember don't argue with a drunk or a fool, it's pointless and counter productive. Make sure everything you can do practically is done and in your favour. Mitigate the impact on you and the kids from him as much as possible,
hard I know, self sooth, mindfulness, keep a diary, all this helps if only a little bit.