Time! I just let time heal the break-up and told myself that as bad as he was a partner, he could still be a good dad, so I had to let him try.
It wasn't something we ever talked about, FOB hasn't changed as a person so I could never have had a conversation about the past for 'closure' but I think it'd have helped. It's a lot easier to be civil now that I am happy, but it's definitely better on Lucas. There's no horrid atmosphere as there's no resentment anymore, I'd like to think we act like a mum and dad are 'supposed' to around him, just not as a couple.