Can't believe she did this .

Out of topic but I just need to let this out , it's killing me ... Just last night my boyfriends sister was with a guy friend getting drunk together , they were in the couch just talking . My bf leave the room to go shower and all of a sudden I hear his sister say his name so i started to listen and she starts telling her friend about the time they had gone out to a club and my bf came back home & fucked some girl in the shower and his sister literally moaned out how the girl was moaning & how all you could hear was her saying " Ay papi que Rico" (Ay daddy it's so good ) that really hurt me . Not only that she talks about it when I'm there but literally starts moaning how loud the other girl was & all the things she said & how the certains of the shower fell and that after the shower they went to the room and all you could hear was te bed banning on the wall ..... I started crying ...... It was like picturing him making love to someone else with such a passion & what hurts more is that we aren't very talkative during sex , it just hurts me to know how into it they were . Yes I started crying and I told him that his sister starts talking about him having sex with other girls on purpose knowing I'm in the room