Am I the asshole?

My boyfriend picked up his 12 year old neice last Friday wich was fine with me but I thought she was staying at our house until Sunday because we both have to work 2nd and 3rd but instead she stayed. Now it's Tuesday, Sunday her mom called me freaking out because we left her alone and I had to leave early. Then yesterday the power breaker tripped and she went to our neighbors house crying 10:00 at night because she was scared so I had to leave work early again. So I told my boyfriend to take her home in the morning because it's not fair to her because we can't spend time with her and be here with her. when he got off work he just come home and went to bed I got angry and told him you are leaving work this time and I'm leaving to go stay at my mom's now he's mad at me am I ta?

Am I the asshole?
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