Long story short, I’m the oldest (26) daughter of my parents. My two middle sisters are still in university abroad. The youngest is 6. I live with my boyfriend in the same city and work for my parents (it’s what I studied).

My parents are well off owners of a business. They often go on vacations, some of which are not appropriate for my youngest sister. At these times they leave her to me and my grandma (also very successful and still working). Now My aunt has some mental health issues (bad ex, not successful at work, alienated all her friends) and lives with my grandma now. She made them move to our village house outside the city because she was scared someone is following her etc. my grandma does everything for her. She also insists she can’t be by herself (in my opinion to avoid having to actually spend time with my little sister), but has gone on a few vacations without her, leaving her alone.

My parents also hired a babysitter to help out. They wanted to let the babysitter stay overnight to let me go out but my grandma absolutely refused. She said she doesn’t want other people staying overnight and talked privately to me that we will make arrangements who will sleep with my sister. I agreed, saying that I only want Friday and Saturday so I can go out, the weekdays I’ll take over. She agreed.

Today (Saturday) as my parents are leaving I’m told that because it’s my aunts birthday my grandma decided she will take my aunt to the city to sleep over too and the three of them + me and my boyfriend will go out for my aunt’s birthday. Me and my parents refused - my aunt can’t be that long around my sister because she causes scenes and I also wanted to make other plans. Eventually my grandma said that in that case she has to stay with my aunt and I’ll have to sleep over (but not the babysitter).

I was in a bad mood over that and ranted to my boyfriend on the phone. Instead of being supportive he threw a tantrum (for the millionth time) that my parents are awful people for travelling and leaving my sister, how I should stand up to them etc. I shouted at him that I didn’t want to hear it and that my parents can go on vacation and it’s not that much of a responsibility to take care of 6 year old. I was mad at my grandma for trying to manoeuvre plans. I’m done with him trying to convince me my parents are awful people. He is mad at me now, pouting that ‘he can’t say anything’ and that I have ruined his weekend and the week.

AITAH?