AIBU to think that my ex is treating his step children better than his own child?

[DaisyYellow]

The only holiday my ex has ever taken our daughter on was a trip to Spain. Last year he went on a UK break with his girlfriend and her children and this year he is going back to Spain with them. Our daughter wasn’t invited to either holiday. The stepchildren are mid teens, my daughter is late teens. I think my daughter is hurt that he seems to be more invested and thoughtful when it comes to them. AIBU and WWYD?

stop encouraging your daughter to do things for him. She doesn’t need him in her life

I know this won't help but this happened to me all the time my dad had 4 stepdaughters and every year they went on a family holiday without me. I now understand that an "odd" number didn't work money wise, the hurt I felt at the time ! I loved being with the girls! My mum would have paid for me and the under occupation fee. I heard my mum saying she will be no expense to you I'll pay for everything for her, still no from him ( them) I as an adult went NC after years of rejection. She should ask him and his wife why he has not been invited/ involved.

Not sure if this is helpful, but DH is 15 years on from the situation you describe. His Father never took DH on holiday, consistently forgot birthdays and treated his new family significantly better. DH slowly stepped away and now has very little to do with him (we receive the occasional angry or passive aggressive demand to visit them). As DH is an adult now FIL has to go out of his way in a massive way to show DH he doesn't matter which is very hurtful. I don't think toxic relationships ever change. I suspect if your DD is being treated like this then the relationship may only get worse and I don't think it's a bad idea to let her step away.