He took his baby mother to water park…

Hello. I am trying to decide if my feelings are valid at this moment. I am 22 weeks pregnant with my first child and my boyfriends third. Yes I know, it’s not as bad as it sounds. Anyway.. a couple of weeks ago he went to the water park with the kids. I was packing up my apartment to move so I didn’t go. I also wasn’t aware of this trip either. I called him and he said him and his family were going to the water park and I was upset because he didn’t extend the invite but I got over it. Well today he tells me, “yeah my baby mother almost drowned when we went to the water park”. Excuse me?? I asked him why didn’t he tell me she was going and he said he didn’t think it was important because it was for their daughters birthday… I’m like okay but you said family. I’m thinking siblings, kids, nephews, etc. It also doesn’t help that her birthday was in June not July and they had took her to the movies together. She’s 15, not a toddler or anything. Would you be upset about this? I’m trying to chalk it up to being pregnant and hormonal but I hate this whole situation all together. It’s not that I don’t want them to have a good co-parenting relationship it’s just what’s next? Trip to the beach? A cruise? Please be honest and let me know if I’m wrong for how I feel.