So sorry to hear your storyFlowerofthewest
My children's father left us when the littlest was just 3yrs old (the one we are having problems with now), we were in a foreign country, he left for another women. He never paid any maintenance from the day he left to now, the next winter after he left, he came round with a new cashmere coat and new shoes, I asked him to buy the children new winter coats as they had outgrown last years, and he just said "no" (no benefit payments there, so I had little money, apart from some sent by my family in the UK).
But even with all this I always let him see the children, as I knew it would hurt them as much as it would hurt him, and I never stopped his side of the family seeing the children. Consequently we are all still friendly, I went on a cruise with my s.i.l and m.i.l 2yrs back and went on a spa w/e the week before Easter with my s.i.l, friend and my daughter, and we quite often have Xmas dinner together!
I'm not too friendly still with my ex, but then he does live on the other side of the world now. He did make a surprise appearance at my son's graduation and my daughters wedding, which to be honest I wasn't happy about, as he'd never been there for them both financial or physically, but I kept quiet so as not to spoil their big days