AITA: my ex says he won’t go to baseball practice if my BF is there

AITA for allowing my BF to come to my kids practice despite their father saying he won’t go if my BF is there?
Background:
My kids haven’t seen their father since Easter due to me taking the kids and calling child services on him. I have emergency temporary residential responsibility so he can still see them but he has chosen to not speak to or see them until recently because we had court and it was brought up. We are awaiting a ruling.

my son asked my BF to come to his practice and also wants his father their. Am I a jerk for telling my ex to grow up and coparent because I put my differences aside with his GF whom he cheated on me with. My BF is an amazing influence on my kids and they love him. I don’t feel like my children should have to choose between the two because my ex is acting childish. Could use some help.