So my little sis is bi and her “girlfriend” is staying in quarantine with us. I say that in quotes since my sister is pretty mentally unstable and always saying she’s doing some weird shit, but apparently they’re actually dating.

Anyways, her girl was showing tons of IOIs ever since we met. We were fooling around in the hot tub when my sis wasn’t there and one thing led to another. For some reason this girl decided to tell my sister all about it and she’s been acting psycho ever since. Normally my first reaction would just be to ignore whoever is getting butt hurt over who I banged, but the fact that it’s my sister is kind of throwing me off. Any advice on how to deal with this?

EDIT: thanks for all the advice guys. I feel like I should mention that my sister is a pretty big scum bag. Stolen money, extremely disrespectful to the whole family and has gotten violent before. Honestly, if she was just a normal girl I wouldn’t have gone close to her GF but the fact that she’s done so much bullshit to me and my fam... I’m not feeling a lot of sympathy for her. Hope that puts things into perspective.

EDIT 2: This was my first ever post on TRP and I didn’t think it would be that contentious lmao but I’m glad y’all got a laugh outta it! Thanks for all the advice, even to y’all that think I’m a piece of shit. I always creeped on this subreddit but I didn’t realize the community was this fucking hilarious. Will be posting again. Peace.