my weird step sis thing

so i just broke up w my long term and its really got me thinking about why i did stuff with this girl who was like a sister to me but in an erotic way i guess? we were both 18+ at the time, but it felt super taboo bcause shes stepsister right. anyway, one day she showed up wearing this tiny dress that hugged her curvy body and had these thigh highs that just said slutty and i got so hard...we ended up going to a hotel and she was into some rough stuff which freaked me out a bit but also turned me on even more. we kept it going for like 3 months, all consensual ofc. i mean its weird right? now im thinking about trying this again with someone new but is that messed up or just my thing? anyone else ever do anything remotely similar?