As difficult as that situation is, I'm proud that you made it about the child and what he can gain instead of the disagreement between the adults. It's a tough situation for sure, I've seen the interactions between divorced parents and it's tense. At the end of the day though, I think the child will be far better off spending the time with someone as good a person as you and your daughter are! Those experiences can have a lasting positive impression in a world full of negative ones. Thank you for doing that for him!