How to move forward from what you have with them?

I can't take things like this, it's fcuking my brain out. I was in a relationship with her for 4 years, she left me out of nowhere, and left me for someone else. It has wrecked my heart into pieces, cause i thought she was the one.

I did everything for her, was there for her in her darkest of times, and she just leaves me like that.

I was really good in my studies , I was class topper of my college batch,I was doing really fine after i fell in love with her. I didn't know how can someone leave 4 years of sh*t we went through together, that involves everything sexually, physically, mentally, emotionally , everything.

And now i lost everything it feels like it. I lost momentum, i lost confidence, i lost relationship, love, job , and now I'm behind in career it feels like seeing my peers moving forward and they don't have to deal with what I went through for the last 9 months.

And yes I'm ready to leave all that behind, but here's what *** me up , everytime I'm focusing, her thought comes in my mind with someone else. And nights are the worst ( you know what i mean),it was 4 years not 4 months that i can just switch off things about her, I'm not being possessive but it's like i had things with her in everyway possible and now she can just easily give it to someone else, can easily cheat on me. I'm really angry, sad, and i don't what am I at this point

H*ll i didn't approached other womens when i was with her, not even as a friend, because i respected her, loved her too much .

Too much can be harmful.

Please help me with these feelings of her with someone else, i beg you to help me stop this, the withdrawals and imagination, no matter I try to stop it doesn't and it's pure agony sitting right there on my chest!?