Boyfriend traveling with ex wife

40F. My boyfriend (50m) and I have been together a year. We both have kids from previous relationships. His daughter is going to college this fall. He’s been paying for his ex wife to attend college visits. I support that. What I don’t support is that he’s been picking her up for the airport in the morning, hour+ out of the way, flying together and staying in adjoining hotel rooms. I’ve told him it makes me uncomfortable, though I do not think they’re sleeping together or doing anything inappropriate, and he says that she has an issue with boundaries and he can’t wait for these trips to be over too. I understood from the get go that there would be instances where both parents will be involved in coparenting, just like my ex and I. However, I think this is a dealbreaker. What would you do?