How do I get my ex boyfriend back after this?

OK I'm going to try and make this short. me and my boyfriend were happy, living together, and he was about to propose. we started having issues and I kept feeling smothered in the relationship so I told him to back off. he wouldn't, so I told him we were on a break. a few days later, I hung out with my ex who I still thought I had feelings for and slept with him. I instantly realized how in love with my boyfriend I was and got rid of the ex, and took my boy back. I never told him because I was scared to lose him. I then deployed overseas, and my "Best friend" told my boyfriend what I had done. he instantly dumped me, but then calmed down later. we went back and forth back and forth for 3 months him saying one day he will take me back, and another day he wont. Finally, he decided since I was on a deployment and he didn't trust me that it would never be the same and he never wants me back. I know know know that if I was home right now, we would be together. its just hard for him to trust me, which I know why, but I wish he'd realize I am150 percent dedicated to him. like literally obsessed with him now. I know he still loves me, and probably always will. but he's being stubborn. now, I finally broke and emailed him even tho he told me to leave him alone- and he confirmed he has a new girlfriend already. its been not even a month since he said he was 100 percent done (which I know deep down he doesn't mean).. so now, I'm literally crying every 5 seconds when I should be here doing my job, while he's over there f***ing his new girlfriend. I'm so so so depressed. and what kills me is I know it'd be different if I was home. I just really desperately need him back. and I know its mostly his friends that tucked him into meeting this girl, because he never goes out and he met her when he went out. I feel sick to my stomach all the time and can't eat . I have never been so jealous/ heartbroken in my life. how do I get this guy back? he told me he doesn't love her yet, just likes her, but that's still making me extremely jealous and ijust want my baby back. please please please help me! please!
How do I get my ex boyfriend back after this?
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