You sound like you have been having a tough time for far too long, and it can’t be that great for the kids to hear / see.
Personally I would write him a letter over a few days / wk and arrange a few date nights / days out / evenings in
and if after that he still doesn’t want to make an effort - find someone who will make you happy - life is too short. Relationships are hard work but you have to want it to make it work (believe me - I’ve had a tricky few years
I hope he can see what he has before it’s too late x