This is really an AIBU but putting it here because I'd rather filter out the people who respond assuming that ex is a reasonable person.
Ex is an abusive arsehole who does not and never has respected any boundary and would not ever take no for an answer when we were together. He continues to try to push boundaries whenever he can and I have worked quite hard to be as low contact with him myself while still doing what is needed for the children's contact. He was physically, sexually and emotionally abusive when we were together and it was realising the negative effect of that on the dc which finally gave me the push to escape.
We have 4 children, the eldest is autistic and more often than not refuses to see his father. The younger children like to see him.
Ex has asked the children to visit with him and his family, staying in a hotel for a few days. I think it's unlikely that eldest will end up wanting to go, but he has expressed some interest in the holiday. Ex has said that eldest can only go if I also go. I said no. Ex says that he could stay in another hotel and I could have a room next door to the children in case eldest needs me. His mum will be going, as well as him, two of his sisters and another adult family friend, but ex keeps saying how his mum is elderly and frail and so it's not fair for me to refuse to facilitate eldest coming if he wants to, because she is too old to cope if eldest melts down.
The thing is - eldest doesn't cope well out of his routine, and does need me at night times. And the stuff they will be doing is not stuff he is likely to enjoy (he is quite a bit older than his younger siblings). So I have had doubts that he would actually go along or cope if he did, but I also don't want him to feel excluded if he does turn out to want to go.
But I just can't go and spend several days having to interact with ex at least several times per day.
I know that in a normal, amicable, split it might be good for the children to see their parents still co-operating and getting along doing things together, but in this case I really don't want to expose them to the interactions between me and ex which are almost always manipulative, controlling and or abusive on his side.
AIBU to say no I won't go on this holiday, even if that means ds1 also can't go? AIBU to feel like it's not my fault if ds1 can't go, when ex says he can only go if I go too?