<human>: My best friend and I are like brothers and have been friends since early on in high school. On his birthday this past December he had sex with my Ex who had broken up with me in the beginning of 2012. She had left me heart broken and throughout 2012 I tried to fix things between me and her and he knew of my feelings for her and how I felt about her. 

The story of the issue at hand being that he was was really drunk on his birthday and took her back to his place and they well.... did the dirty. 

Now I'm more disappointed than anything at my friend and I don't know what to do with him.

Can you succinctly summarize the text in 1-3 sentences?
<bot>: My best friend had sex with my ex girlfriend who I was going out with for a year. Now I don't know what to do/say to him.