fucking my best friends brother

iv been friends with these two for 12 years now(im 23,besties 22, her bros 19) me and my bestie are still always hanging out and so is her brother who iv been hooking up with for a few years we get off on the thrill of it sneaking touches and kisses hes fingered me under a blanket while we were all watching a movie and sucked on his fingers acting like it was chip crumbs lol we like going out without her to let people see us together she has caught us kissing once and we played it off as I was teaching him how so he could get a gf which she bought since he never had one at that time. we have the best sex and he always comes back for more he likes it I like he fucks me really good and he even has a gf right now and we still fuck he told me she complains they dont get intimate enough oops my bad lmao I don't think we will stop since we will all be friends for a long time as long as she doesn't find out and like hate us for fucking each other crazy