I also agree with C. For the time being, make it a point to show them how much you love them. Make up for the lack of goodies. Emphasize to them what we all already know: It's about the love and togetherness. Being with one another. That value is something you can give to them that you're swamp moster ex can't.

The whole "Santa isn't visiting daddy's house" is some low, low shit. However, kudos to you for remaining above such a low level.

You're a smart and resourceful man, Res. You'll figure out how to make it work for the time being, I'm sure. When your kids get older and are mature enough to completely understand the whole situation, then the ball will be in your court.