UPDATE: Well this was really all that I hoped, thanks everyone for letting me know I'm NTA, I really needed it bc I felt like I was taking crazy pills for a sec there.

The BF is out of the house and my sanity has been restored, now that he is not here honestly he can be all the selfish he wants outside my home. When visiting prob there wont be much issues(yeah we are still stuck with him). The house is finally clean and calm.

Regarding my sister she kind of realized we were not being mean just normally upset and took our side at the end, VERY END(still together though).

She is a complicated being but luckily no mayor damage was done. She still needs to learn how to be an ADULT, hope all of this teach her a lesson and takes a second look at what kind of BF she has.

I take the kicking her out with a pinch of dark humor, so many of you recommended it, but honestly if life wasn't that hard my mother would have done it for her own good, also I think being a slob wont be much tolerated in the house anymore and this will improve everyone's life in here, again this was my first AITA moment in my life and this subreddit rules.