what to do ?

okay so my best guy friend shares the same kinky stuff as me. He likes to go rough and choke people during sex and I liked to be choked. I can be tied up and all this other stuff.

Okay, so we’re seniors in high school and we joke about doing things together, but I found out recently that the last time we talked, he was being serious. The thing is, he has a girlfriend. His girlfriend knows how he feels and is totally okay with it. I’m just wondering how anyone is okay with their boyfriend having sex with another woman?

We graduate in 2 months and he has a plan to do it with me then. Even though his gf is okay with it, I don’t think I totally am. I mean I want to so bad but like I would feel weird. Sometimes I’m just like “suck it up and do it anyway” but there are doubts. What should I do?