Passports

Hey mommas, my ex broke up with me and stopped communicating with me 3 months ago. We have two sons an 18 month old and 4 month old but neither have passports. I’m looking to do them tomorrow but because my ex is on both their certificates how does that all work? I’ve been told both parents need to sign. I have tried contacting him since but as him and his new girlfriend are together she doesn’t appreciate him talking to me. I was planning a family holiday with my parents and siblings for August but if I don’t have their passports I won’t be going. Any advice I’d love 🥰