bit of a aibu really, but anyway, been split for 4 months, ex living with nw and her 3 kids. He sees our 2 children about once a month, and we due to have them in my house all this weekend. But it turns out it is his gf's son's birthday today, so he only had our daughters yesterday, and left early to spend today with the gf and her family. I think he should have spent the weekend with his own children, instead of a boy he has know for a few months, or is how it's going to be from now on?