Information about cheating was minimized, now I know all

I am in a long distance relationship, we were together for a year before the long distance started. The plan was university abroad for 3 years and then (talk) about getting married. Within three months after the move, I found evidence of cheating on her facebook. I asked mildly about it, but she denied it. In August of 2016, 5 months after the move, I confronted her about it and she admitted it, but denied anything intimate, but she choose to break up with me rather then agree to see other people.

About two weeks later she started texting me while with the guy, and a week later called me and said that she had made a mistake and regretted it, and asked if we could get together again. I asked about the details about the cheating and again, she minimized everything that happened. I just happened to have vacation that week, and I ended up getting on a plane and flying down to see her. I was really happy to see her again, and when we were together I asked again about what happened. Specifically a trip that I was sure that they went on together and had become intimate. She STRONGLY denied it and insisted that she went with friend, and though I didn't really believe it was possible, I wanted to believe it so I accepted it.

Fast forward to February of 2019 and we were together visiting her parents to let them and everyone know we were planning to get married. After we got home and separated again, I called her early in the morning and somehow she brought up the topic of her gold coast trip. I replied very quickly "the trip you went on with your boyfriend" . Her immediate response was "yes" followed with a face which was a "Fu#%, I've been caught" face. Followed with my question "Where you obviously had sex right?" and her first honest answer.

Later that day, for the first time I got what I would call the complete truth of exactly the full scope of the cheating. When I went to see her in September of 2016 I knew, suspected, what the full level of cheating was, and I think I was really prepared to forgive her and move on. But when she lied to me, I think I also just wanted to believe that.

Now, It's a full 2.5 years later, I feel that we have grown closer and more intimate, and I do believe her that she hasn't cheated on me again....mostly believe. But I am having a harder time excepting it and moving past it.

I asked for, and got, the details of their relationship. And I believe she was very honest about it. Part of it is I feel, like she was much more selfish than I pictured or accepted in my mind. She very well knew that she was seeing two men at the same time and lying to both of us. I had an image of her being
"immature" which lead to the cheating, but now I see her as not only an active participant, but really the one in charge. She knew what she was doing and really didn't care or have any guilt that she was doing something wrong at all.

Five months after we got back together I randomly clicked on one of her old facebook photos that was from the time she was cheating on me. In the comments section was a guy with the comment "My girl". Of course I was curious, I clicked on his profile. His profile picture was him and her together clearly on a date, and his first timeline photo was him and her sitting on the beach together with the caption "with my love"......It was dated one week earlier. She told it was a crop of a mutual friends birthday party, she didn't know he was going to be there, and it was a picture of everyone that he had cropped out so it looked just like them. I could see it was cropped that way. At the time I couldn't understand how she could keep ANY contact with him, but again I wrote it off as naive. Now...knowing what really happened, I really can't understand it. It's just common sense you cut the person you had an affair out of your life. She didn't. She tells me there was no other contact, and through a weird twist, he contacted me wanting to know about me. I believe her.

The last thing is........ she never told the truth about it. She never accepted responsibility or gave me the fair information to make my own decision on to stay or leave. She says she has regretted not telling me the truth every time we have met, but she has never tried. I think if I hadn't trapped her, she would have married me without ever telling me.

For the last two and a half years, our relationship has been fantastic. I deeply am in love with her, but only know do I feel I know her better. I really want to forgiver her, but I think I need to have empathy for her to do that. When I think about how she cheated, really on two people, how selfish it was, how she really didn't seem to care, how she didn't FULLY cut him out of her life after it was over, and how she could never give me the honesty that I have been asking for for so long.....I just can't understand it.

What I am struggling with is, am I being to hard on her for something that happened 2.5 years ago. Am I being too righteous and moral. She says she is really sorry and will wait for me however long it takes. But there is just no way to know if someone is "who they are" or can change. More than the cheating, it was just really unfair to keep the truth from me for so long, and let my feelings grow.

I know the advice for this is "Only you can decide". I know this. But I would like to hear thoughts, or experiences. I'm leaning towards finishing it.