You're a lot nicer than I am, I would have lost it on your fiancee. By him not saying anything, and not sitting with you and your kids, he was being very disrespectful. Family or not, you're the one he's chosen to have his own family with, he needs to realize that, and you and your kids come first. Next time something like comes up, I wouldnt' even fake sick. I'd flat out say no. If he wants to go, that's fine, but he's going alone. You don't need people like his family in your life. Just cause he's stuck with them doesn't mean you are