Why is my mate doing this?

as per my previous questions its regarding the situation between my best mate and my former fiancee. They will soon be getting married and he just seems to be rubbing it in my face as he knows that i love her still so much and we only been away from each other a year. he says he is going to hire out a Lamborghini for his big day. i know they say blokes are not supposed to cry but i cant stop thinking about it all and how it should be the other way round. I really try to live from day to day just going about my business but i cant, truth is my mind will not let me every where i look or do i just see her, she is so beautiful inside and out and it makes me so sad its unbelievable im deeply depressed and stupidly suicidal im crazy about this girl I know people say if you truly love someone you would want to see them happy no matter who they are with, but with me i have jealousy, anger, frustration, hate and depression rolled in together as i want to be the guy next to her not my best mate i just cant seem to get over this situation and her, what is the best remedy for this as im so down in the dumps it hurts to even wake up to face another day