what would you do

So my bf’s family is going on two vacations. The first is out of the country and he refuses to go since he wants to spend that week with me. The next is to a beach 8 hours away. I don’t know this for sure but I’m worried about his uncles gf bringing the kids she has custody of. Three years ago at the same beach she brought them and one was a girl my bf’s age. I was super busy moving into college and barely taking to him but later found out that everyone was joking about them kissing on the beach etc. I was pisssed and then also found out that she wanted invited to Christmas eve at my bf’s last year. I have seen flirty texts between them two years ago snd told him to knock it off or it’s over. I also could tell from the texts she wasn’t interested. She’s super pretty and I know my bf thinks the same. I saw him searching her on fb (he blocked her when I saw the flirty texts years ago since he told me he wanted to date me). I know that we are older now but I’m worried if she’s gonna be there. I was invited to go on this trip but don’t want to feel like I’m going to babysit him but also don’t want them to be together. I’m also worried that he wants to go on this trip if he knows she’s going. He never told me that she was going to his house for Christmas eve so I had to find out on my own. Sorry if it’s hard to read trying to work and post this! Also I trust him around anyone else a million percent I just have bad vibes about this girl since it’s also obvious his parents love her.