Whos at fault for this.....?

so my bestfriends name is stacey. i went out with this guy,rodger, that stacey hated but she understood how much i loved him soo didnt care with us bein togethr. me and rodger broke up but stayed friends. well one day rodger came over and told me he still loved me. i was sooo happy cause i still loved him. i called stacey right away and told her wut rodger said to me. she was happy for me. i went on vaca with my family to the shore. wen i was at the shore stacey called me and told me she was hangin out with stew the kid she had a magor crush on. well wen she was hangin out with stew she ended up hangin out with rodger too, cause stew and rodger are friends. well stew had to leave soo stacey stayed with rodger and his othr frineds. stacey and rodger hooked up that night. (stacey new how much i liked rodger and new wut he said to me 3 days before.) rodger texted me then next day tellin me wut happened so i called stacey and asked her. she denied the whole thing. well of course i believed her. she ignored me for 3 days. and finally told me wut really happened. her excuse for evrything was "i couldnt say no". im not mad at either of them but rodger now likes stacey. im still inlove with rodger. i just wanna no who is at fault wor wut happend and wut should i do?? please help!