Don't start lying to your kids, 2tP. Once you start that, you've really lost your own integrity. Your kids need to know that you're the ONE person in the entire world, that will ALWAYS tell them the truth. They ESPECIALLY need to know that NOW.
If your wife doesn't want you to go, and this is her family's event, then I think you should honor her wishes. But I don't think you should lie to your kids about it. "I told your dad that I just needed some time by myself with my family right now, and so he's staying home this time" (or something similar) would be fine.
The only thing worse than lying to your own kids, in my opinion, is allowing your wife to dictate how and when you lie to them.
