Can't let go

Hello...I have been through so much this past month and i really need some advice on how to deal with this... A week ago my boyfriend of 3 1/2 years broke up with me. His reason was b/c he wanted to be free and spend more time with his friends. But...a couple days later I had found out that he was cheating on me with like 5 different people..possibly more. I was so devastated that I lost weight, wouldn't eat, couldn't sleep, cried 24/7. I loved him so much, and he told me that he did too..i mean 3 years is a long time to be with someone, and we had planned on getting married and everything. I had seen signs, but I didn't think it would come to this. He was spending more time with his friends lately and he would never want me to come with. I just don't know how to deal with this. I still love him so much even though I know what he did to me is beyond forgivable. It hurts to know that he said all those things and promised me so much but turned his back on me and left me with nothing. I will always love him and will always think about him and the memories we have together. I don't think that I will ever be the same again without him. I still wish he would come back to me and tell me that he needs me and he loves me b/c it's what I want..but yet I can't go back to him b/c of what he did to me. How do i ever get over this and move on...and how do i trust again...and how do i stop thinking about him and wishing that he was with me. HELP please... Thank you so much...