I honestly don't know if I'm being selfish here or if my feelings are justified. For context I'm 46 year old man, my wife is 44 year old. We've been married for 10 years. It's the second marriage for both of us after divorcing our previous spouses. My wife has three kids from her first marriage (17 boy, 15 girl, 13 boy) and I have three kids from mine (19 girl, 17 boy, 15 girl) so parenting the kid's wasn't new for me and that worked well with my step kid's When we got married, my wife's kids mostly lived with us. Their dad had them on weekends, so for the last 10 years I've been heavily involved in raising them. School stuff, sports, helping with homework, driving them around, birthdays, being there when they needed someone to talk to, all the normal parent stuff. I've never tried to replace their dad, but I've always treated them like my own kids and we've always had a good relationship. Last weekend all the kids were talking about plans for my oldest stepson's 18th birthday next month. What he wants is a trip with just his biological mom, biological dad, and his two full siblings. No me or kids, my kid's going to hurt if they know what actually happened but I'm not telling them also they are excited for their another sibling who turing 18 and we were talked about it once His dad is paying for a pretty big trip. Apparently a week on a yacht and then a few more days traveling elsewhere it's mix Italy and Spain. My stepson said he wants his 18th birthday with his "real family" because it's a special milestone and they'll never get another chance to do something like this together. I'm not going to lie, hearing the words "real family" hit me pretty hard. At first my wife told them no. She said it didn't feel right and thought it would be hurtful. But after a couple of days of the kids talking to her about how much it meant to them, she changed her mind and agreed to go. Now I'm sitting here not knowing how I'm supposed to feel.Part of me gets it. They're her kids and his kids. Divorce is messy and maybe this is something they've always wished they could have had. I don't want to make an 18 year old's birthday about me. But another part of me is hurt I've spent 10 years helping raise these kids. I was there for the day to day stuff, not just the fun weekends. So when they talk about wanting their "real family" together, it feels like I'm being reminded that no matter how much I've done, I'm still not really part of that family in their eyes. The other thing I'm struggling with is my wife going on this trip in the first place. Maybe this makes me sound insecure, I don't know. I trust my wife. She's never given me a reason not to. But I'm honestly not comfortable with my wife spending over a week on a yacht and then several more days traveling with her ex husband. Yes, the kids will be there too, but it still feels weird to me. If I told my wife I was going away for 10 days with my ex wife so we could play happy family with our kids, I have a hard time believing she'd be completely fine with it. But I'd be lying if I said I wasn't hurt, excluded, and uncomfortable with the whole thing.