You. Fucking. Can.
You feel like you need her in your life, that about right? Bullshit. I've been in a similar boat and it fucking tears you apart inside. I know exactly what it's like to see someone you care about so fucking much just go into another's arms, happy as can be. Worse still, she lied to me. She just kept telling me that she wasn't ready for a relationship, when in reality, she was seeing someone else, but didn't have the heart to tell me.
You're gonna hurt a while. No one can really help you except yourself. The hardest part is accepting things for what they are. At best, you can keep contact and be nothing more than friends. At worst, you cut all ties and move on. That's life. You're going to hurt, and you have to make the best decisions for yourself. Nobody else can do that for you.
Pull yourself together first. Then try to bring yourself to talk to her. If you can't, it should stay that way. It's probably for the best. >Pic related