I’m a 23M and my 18F sister in law and my girlfriend (20F) want to explore polyamory and nsa sex with me. I don’t know what to think.

I just got out of a weird conversation with my girlfriend and my sister in law. Apparently my sister in law (18f) has feelings for me. My girlfriend (20f) is ok with it. In fact she was the one who brought it up. She said she’d like to try something different. (She had mentioned this to me before, but I never thought it was that serious) She said it wouldn’t have to be a relationship, just that it could be fun. So at first, I was like “what? That’s too weird to be real. I’d never go for that. I’d feel guilty”. But now I’m seriously considering it. It’s just so out of the ordinary. So I asked her, just to be sure “you’re sure you’re ok with that?” She said yes. I’d never thought about it until now, but I’d totally be down for it. I read about it and sister in law/brother in law relationships are way more common than I thought. Plus, they just seem like they’d both be into it, you know? I’m not sure if I should tell my wife or not. I feel like she’d have to know. It’s weird, because I’m not sure if my relationship will survive this. I can’t tell my parents. They’re too religious to accept that at all. I’m honestly not sure if I should do it or not. The worst part is I’m not sure if my relationship with my wife is over. Most people won’t understand this, but I really don’t know what to do. I don’t know if it’s worth it. I don’t know if the thrill of the taboo situation is worth it. I don’t know if I’d rather not tell my wife and juggle two women. I’m not sure what to do. <br><br>Tl;Dr: my girlfriend and her sister (my sister in law) want to explore polyamory with me and I’m considering it. <br><br>EDIT: this is fake. I was bored and decided to post fake info to see what you guys thought. Thanks for the advice, but I don’t actually have a problem.