Coparenting issues

Im kind of upset and not sure if i should say anything or not. My daughters dad and I did not get along at all for the first year of her life, and finally for the past 3 months we have been doing great at coparenting and getting along so well. Well last weekend him and his girlfriend broke up and when they did he told me that she didnt like the fact that me and him were friendly and that she made a big deal about us wanting to take our daughter to the fair together (mind you, she would have come with us aswell). The day after they broke up they got back together and he has been completely different. So short and has hardly even texted to check on our daughter (i have full custody so he hasnt seen her all week). Before the comments start, neither of us have any feelings for eachother and know we are never getting back together, we were just coparenting so well until this week. Should i say something to him or let it be?