[FULL] Perfect Girlfriend's Dark Past: Why I Ended It

Did my two-year relationship end after she told me about how her last relationship ended? Everyone wants me to reconsider, but I'm not sure I can. I, 32 male, have been in a very serious relationship with my girlfriend, Anna, 29 female, for over two years. To be perfectly honest, Anna is perhaps the best thing that has ever happened to my life. She is perfect in every single way, and I sometimes feel that Even early on in our relationship, I felt that she was the one with whom I'd start a family and grow old. Literally everyone I know loves Anna. My parents, siblings, friends, and even my co-workers think we are a really good match. I have met all of Anna's close friends and family, and like my own, they all happily accepted us, thinking we were the perfect match. I am not joking when I say that 99% of the time, our relationship felt like the honeymoon phase. I had not been in a relationship for three years before we started dating, and from her friends and herself, I've heard that her previous boyfriend, Ian, was a good guy, but they just didn't see eye to eye on some issues. Beyond that, I have never really thought too much about Ian. Anna and I tell each other everything, so I always thought there wasn't much else to the story. Apparently, I was very wrong. On Sunday, November 12th, Anna and I were at a small cafe, enjoying some drinks, when she started talking about how serious our relationship is now, and that we needed to be transparent about everything. I listened carefully but didn't think too much about it, since I believed I knew nearly everything about her. I became more attentive when she started talking about how she felt she could tell me anything, including how she and Ian broke up. I became interested in this and asked her what she meant, as I was under the impression there wasn't much else to her story. She seemed uncomfortable, and then finally said that she and Ian had broken up because she had cheated on him. To say I was shocked would be a major understatement. In the entire time I had known Anna, I would have never imagined she'd be capable of something like that. Anna noticed how shocked I was, and said that she had made a terrible mistake at the time. She had severe depression due to grad school and many things happening in her personal life. She told me that she cheated on him for about a month before he found out, and ended things with her. She had begged him to stay, but he refused, and that was that. At this point I was too stunned to say anything. We completed our meal in silence and headed back to our apartment. The next few days afterward were a blur, and I remember that we didn't speak much for most of the part, partially because I felt I would never be able to come to terms with the fact that Anna had the capacity to cheat, and partially because of our work schedules. On Friday, I sat down with Anna for our first real conversation since Sunday. I told her that I didn't think things between us would work out, and that I wanted to end our relationship. Anna cried a lot and begged me to reconsider, but I told her that my mind was made up. After the conversation, she went to stay with a friend of hers. I texted her, offering to keep her stuff in my apartment until she found a place of her own, and then she could move out. Her only response was that she wanted us to think things through once we've cooled off, and not decide anything drastic until then. Honestly, the whole thing has just made me feel miserable. I feel like the person I thought I was going to spend the rest of my life with was a lie. I've spoken with my friends and family about the issue, and quite a few of them think that I should look past this as Anna is amazing in every other way. A few of my friends even think that I'm being unreasonable and too cruel to Anna. I feel very conflicted and miserable with the whole thing, and how it ended. On one hand, I feel that Anna is perfect for me. On the other hand, knowing that she can cheat, makes me think that I'll never be able to trust her. I feel that the people in my personal life know the wonderful person Anna is, and for that reason generally think we can work it out. Which is why I'm posting here for some insights. Am I wrong for breaking up with Anna after finding out why she and Ian broke up?