Has anyone else gone through this guilt of existance?

This has been on my mind for about a year, eating me.Thought it would be easier posing this question online than people I know. It begins 5 years ago,when I met this girl in high school.She was perfect, smart,beautiful,funny but a bit nuts.She was obsessive and sometimes would hurt me just to make herself better..I’m not saying I was a Saint either, but as near one could be.I helped her through her troubled family, and got her to study harder, and I took care of her. At first, she was scared of intimacy.We shared our first kiss 3 months into the relationship, and as she wanted to remain a virgin when she married (me), we engaged in anal intercourse about 6 months later. There were times, she wanted to lose her virginity,but I remembered how much it meant to her, and refused all those times.Later, she would thank me for not giving in. Then my grandfather whom I loved a lot, died in front of me because of a heat atack.From then on everything changed.She wasn’t there for me emotionally, and all she would do was complain, and obsess about something, and inside of me I felt that it didnt matter. There was more to life than this.And she made me sadder as time went on. Forward a few months, and I’ve left my country and have gone to University.I tried to maintain a long distance relationship, because I did care for her, but she mad my life hell. She would flood me with e-mails and guilt me into talking to her instead of socializing and meeting people I would spend a large portion of my time with.She kept referring to the people around me as sluts, and how I was going to be corrupted.And it took its toll on me. I decided to take a week break from the relationship to get clear head, and I find out, that she had phone sex with my best friend in the mean time.My friend cried and aplogised while she blamed me. I dumped her a minute later. As time went on, at the back of my mind, I felt we would work out.And then she started dating someone else 2 months later.I missed her and felt I made a mistake, and tried to get her back before anything progressed too far, but she said I had hurt her too much. And then in September, she casually mentioned how she had lost her virginity to her new boyfriend. The kicker is this, he dumped her because his parents felt he should date someone of her nationality, and 2 months later he was dating someone else of her nationality.She was played, and when we talked she seemed to blame her problems on me.I took it with a pinch of salt and kept trying to move on. But right now, day by day all I can imagine is this woman I once loved, having sex with someone else who didnt care for her, while I tried to make amends.I do admit Im being selfish, I didnt have sex with her when I had the chance, and I didnt try and work things out.And its 3am and Im lonely.I’ve met many women, but all I can think about is how they arent as good as her.But at the same time, all the pain comes back.I miss having someone, miss her to a degree,and I carry this guilt with me and its weighing me down.I miss her, still do, but I never want to be with her (not like shes running back to me anytime this millenium).I hate her, but miss what she stood for. I havent even been able to hit on a woman because all I think of is her. I wondered if anyone had gone through something like this.