passport complications

so my child father dont want to sign both our kids passports idk why ! my family is having a big vacation to see my grand parents but yet he still wants a relationship with me ! i do everythin for his kids our kids and the least he can do is that and he wont ! he is upset i took them to take their passport photos without him instead i went with my father and now he says things like “ u act like they dont have a father “ my dad also set an appointment to get the passport application done and he never showed up to sign it .. now i want to leave him ! but he still tryin to be with me