Will NC Work In My Situation? (It’s complicated)

This is going to be pretty lengthy so hang on. Essentially I had been dating this girl for 3 years in which we had extreme obsession and love for one another. She’s the love of my life. We argued here and there but nothing out of the ordinary. I ended up making a huge mistake and hooking up with a girl I had known for a pretty long time. I broke all trust and knew that I had damaged her. I came back immediately and tried to fix things and reconcile with the girl I loved. We did not break up. We stayed together I had improved on answering texts faster and answering the phone more because those were areas she disliked that I lacked in. And then all of sudden she broke up with me last July. Even after breaking up we stayed in contact, hooked up, everything but I sensed her slipping. She became more reluctant to hang out as months passed and I had heard rumors about her seeing her coworker so we argued more and more. I became insecure about this new guy and she lied and told me she doesn’t hangout with him and hasn’t done anything with him. I then found out she hooked up with him and had feelings for him due to him being positive energy when we were not doing so well. Eventually I found out about this guy. And started begging, I made critical mistakes here. This is around October of 2017. (Yes this is still happening). She would text me still and tell me that she liked this guy but its nothing crazy but essentially put him over me and started ignoring me somewhat. I begged for 2 weeks. And eventually I texted the guy and asked him what had been going on because I was still in the picture. He had no idea that she was still contacting me. He then left her and she was devastated. She found happiness in this guy while still being with me and I feel like she took me for granted. She came back in November and we had started having some fun. I changed! I took her to a festival, I was offering more emotion, bought her flowers and chocolate on a regular basis, did everything correct. Except act insecure, I would ask about if she had still been in contact with this guy and if she liked me anymore and if she was happy and she ended up lying about being in contact with this guy for months. I found out 4 times and she begged that she would stop because she loved me and would change but never did. She ultimately ended up leaving me in February. She still remained in contact with me every day and even hung out with me! I had asked if she was still in contact with this guy and she informed me that she was working on herself. Then all of sudden in late February, the guy approached me in the gym and stated she poured her heart out to him with intense feelings. (Which felt like a knife piercing me in the stomach). I asked her about it and kind of felt betrayed she had been lying for several months so I kind of blew up on her and she blocked my number and said that I was a ****. Throughout March and now April I have begged to see her. The last time she saw me was March 1st and she kissed me goodbye and cuddled with me. After that she said she wanted space and didn’t call for two day increments and then I would break and call her once a day to ask why this was happening and what I could do to fix it? Two weeks ago she used to call on “No Caller ID” and she would say she missed me and what not. I went on a 7 day NC trial before I found this website and ended up caving in. I’ve left voice messages of me in tears, i’ve begged for almost two months, and even compared myself to the other guy and talked somewhat negatively about him unintentionally (he badmouthed her when he spoke to me but she doesn’t believe me). She just started not calling back and ignoring my texts. Yesterday I had got her to crack and she called me for an hour after I had said this isn’t right and that she should come back because I changed. She stated verbatim “I’m not over you, I miss you, I think about you every day and sometimes most of the day, sometimes I cry over you because I still love you and I like you. But I do not want this relationship right now, if we’re meant to be we will be, I’m never too far.” And I essentially cried like a girl on the phone and stated how does she love me if she wouldn’t give me another chance. I then asked about the guy and she told me that he is not a rebound and that she has feelings for him because he is older and fun and it is new. Despite her telling me that he is not a rebound I feel like he is. He came immediately in my relationship and has been here for months now on and off. She states she is happy right now and that she tells him that she doesn’t speak to me without him asking (she just informs him so i’m afraid she’s trying to be serious with this guy), but then on the other hand she states she has no answers for what they are and that she doesn’t know what’s going on, apparently they don’t talk about feelings or dating and he doesn’t take her out on dinner or anything like that (I feel like she likes him more than he likes her), but he did just go to her formal dance (she is in a sorority). 3 Hours after that phone call I called back to be casual and it ended up getting into a fight with me begging because I get scared and try to convince her. She then stated that I lost her for now because I cheated a year ago and she isn’t happy in the relationship and she can’t commit right now and hung up. She called back and said goodnight peacefully. But this other guy also got out of a relationship around a month after me and her broke up. He still loves his ex. They don’t post anything on social media and people don’t know about them. And I feel hopeless at this point because I just want my girlfriend back. I’ve pushed positively and negatively with her arguing and being extremely nice with mood swings because I find out lies week by week. Today is day 1 and i’m afraid of actually going through with NC, will this benefit my situation or cause more harm? Do you think she will come back? Do I have a chance?