AITAH for not inviting bonus kid.
Sorry...it's a long one!
Context: During the virus days my bio child "A" ask us to host their friend "M" when colleges shut down. We agreed and they lived with us for 5 years, even calling us mom and dad. They eventually moved out of state to be with thier partner.
While they lived with us, about 6ish years ago, I planned a big vacation and invited my married bio child "P" and thier spouse "L", my two bio kids "A" and "B", and "M". As I was planning "M" made serious accusations against "L" and despite my warring bells going off I rescinded the vacation invite to "P" and "L". After I paid the vacation off, "M" decided not to go, and I could not add guests to the package. Later, I found out the accusations against "L" were completely fabricated. I was upset and hurt over everything.
Last year I started planning another big vacation for later in 2026. I again invited "P" and "L" as well as "A" and "B". I did not invite "M" or thier spouse. "P" and "L" has made it clear they want nothing to do with "M", understandably, and I wanted my vacation do over. "M" has lived out of state for over 4 years with thier partner. They would call only when they needed something, i.e. money or visit if they were in town for medical issues. They rarely communicated with us or my kid "A" whom they say is one of thier best friends.
In October, "M's" life imploded with medical issues and spousal issues. They asked if they could move back in with us and we agreed. We paid for their move with our vacation money, added them to our vehicle insurance and helping them where we can. They are finding it hard to find work (this is true), they are having serious health issues, thier spouse is facing life challenging issues and they have decided to divorce. Despite all this I've been paying off vacation packages and booking flights. I was not giving up this vacation.
Recently, "M" talked to my spouse about how hurt they are that they aren't going with us on vacation. Spouse explained the reasons why: mentioned the previous vacation debacle, that when they were out of state they rarely called or talked to us, shortage of funds from helping them move, and that we wanted "P" and "L" to go. "M" brought up that "P" and "L" live out of area too, and spouse said that they still call and text if not daily at least weekly. My spouse has agreed with me that they should not go, but I feel guilty. My bio kid "A" is caught in the middle. "A" has stated that they are not upset that "M" is not going but upset that "M" is upset. So reddit, Am I the AHole? Should I make changes and add "M"?