Yes, it's pretty likely there could be some badmouthing of FIL, but by the same token sometimes all the children can see is that daddy has left them. Maybe this new guy is a total dork and they are ****ed at daddy cos they are stuck with some new bloke at the dinner table.

Just my 1500 cents
Lol, thanks Lulu. I think the problem is that the new guy is just like a brother (as I said, he's younger than my DH) and totally 'cool' and not like their grey old dad

Dad didn't leave, mum did and that is the sucky part to me. Parents crap should be between them, unfortunately that is never the way it works.

He definitely wants to be a part of their lives but has had to deal with not even knowing where they are or being able to contact them at all. It has taken so long for court dates and stuff to come round that they no doubt feel like they have been neglected, but not for lack of trying on FILs part.

SIGH, such a sucky situation.