My 19-year-old sister has been living with me(26M) and my fiancé(25F) for 4 mouths now (for school). When she moved in I had only 3 conditions no alcohol, to tell me if she will be late and no boyfriend home. If she does that then she can live with us as long as she wants rent-free. I gave her the 2nd floor, and I live in the 3rd floor.

Yesterday she broke one of the rules, she broung a boy home, when I confronted her about it she said something like ``I don’t know why you are angry he is just going to help me with something`` and ``he live far from school``(I live about a 10min car ride from the school). I shouted at her that she lost my trust, the boy tried to intervene but I quickly told him to shut up and not to get his nose other people’s business and to get the f*** out of my house before I kick him out myself(he left after that). I was angry at my sister and in some way kind of sad, I felt like one of the persons I relay the most on has just stabbed me in the back.

I was visibly upset, she knew it because it was the first time that she saw me this angry in front of her, she apologised and tried to hug me but I stepped back and told her to pack her stuff.

I then locked my self in my room and called a friend of mine that work at the campus linked to her university and got her an individual room.

today I helped her to move there. after finishing, she tried to hug me again but stepped back and left.

So AITA in this situation.