One of my closest guy friends ruined my relationship with my gf what do i do?

Its been about a month since i broke up with my gf of six months and well i just notice that one of my closest guy friends is 99% most likely the reason for why she broke up with me. He was friends with her at the time and i was obviously more than friends with her, but now they are dateing. he weasled his little *** in and took her from me when he had the chance because i trusted him and my trust in him got me nowhere. iv lost soooo much respect for him i just wanna kick his ***!!! or confront him! what do i do? i had accomplished so much in this relationship id say i had accomplised what most accomplish in two yrs in six months. and he trys to keep their relationship secrect so i dont know and iv obviously figured it out what do i do ?????