It seems the dynamic that ‘worked’ IN the relationship is causing problems/resentment after it’s ended…
Sounds like dad was the breadwinner and that worked during the relationship. Dad did his duty, mum did theirs.
The relationship ends and dad’s now being shunned for continuing with the duty he once was responsible for.
Sounds like dad should cut back work, or do another job which allows him to be fully present when he has the kids, and mum should get a job for the times she doesn’t have them. Great in theory, pretty difficult in practice. You can’t shun one parent and not the other.
Clearly mum and dad didn’t appreciate each others effort IN the relationship, and that’s now created/added to resentment, but with a child in the middle. If the ‘new life’ was a bit clearer to both, maybe the relationship wouldn’t have ended 🤷🏽♂️
Also I notice a fair bit of mentioning mums mental health, but what about dads? What about the impact it will have on him if his children were moved further enough away that restricts his access to them, and that naturally his bond will decline slowly over time. I guess he’s the dad, he’ll get over it. It’s all about mum. It’s not right. It’s about neither.
I’m digressing, I have my own situation similar to this one. Have gotten a lot of value reading this post, hopefully things worked out for the kids and both parents.