SD is 11, have been with her dad for 5 years, mum is not involved. DP has to go away often for work and I work from home so look after SD while he’s away. This is mostly been fine, she has the option of staying with grandparents but chooses to stay with me.
I also have a 12 year old sister, our mum has quite a few problems and as I am older, she has stayed with me on and off since she was a baby.
They are completely different but have settled into a friendly but probably not friends relationship and there has never any major problems between them. I have been looking after both a them for about a week. They go to different schools and do different activities so don’t see each other that much but when we’ve been together everything has been fine and they both have seemed happy.
Sister went back to our mums today and SD came to me in tears and showed me some extremely nasty and embarrassing messages sent from my sister to her last night, I comforted her and said I would talk to my sister, she cried for me not to and said just not to make her see her anymore.
Sister said she had no idea what I was talking about and that there were no messages on her phone, was asking what they said and why she would do that, I’m 99% sure I believe her. I was already thinking the wording and content of the messages didn’t seem like things my sister would say and more likely that SD sent them to her self.
I feel completely torn between the two of them and can’t see how I can sort this between them or know who is telling the truth.
AIBU to choose my sister over my stepdaughter? And to say SD has to go to her grandparents if DP is away and my sister wants to stay with me?