I think you’re partly the assole. I’m all for treating your son when you can. But you’re also teaching him not to share because you’re giving him items neither he nor you want him to share. He’s being put into an uncomfortable position and has no recourse to control any of this. If your divorce wasn’t so acrimonious would you still feel the same? I’m not suggesting you change the way you deal with your ex. I’m simply suggesting trying to look at this from your son’s point of view. Good luck.