Im killing myself mentally because im unable to move on?

she's with her new boyfriend doing god knows what and here I am wishing I was with her. I can't stop thinking and wondering what they are doing. I hate the fact she will be having sex with someone else. It literally feels like my heart breaks every time I think about it or any intimate moment really. I can't let her go she's way to important to me but im literally killing myself mentally if I keep hoping. I really dont know what to do. I still talk to her a little bit but just as friends. Im really hoping they break up soon but it sounds like she likes him a good amount. If Im still not over her and she gets married I honestly dont know what the hell ill do.
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