T something may well be up but from my experience it's better not to go looking for it. I'm sure if he married OW he would have wanted your kids there (if only to ensure that you got to hear all about it). It's probably all to do with the papers he wanted you to sign.
Me 43 XH 45 M 2.7.88 Divorce 7.10.09 Kids D20,S17 & D15