Search Results: still love ex girlfriend

A few years ago, my ex came back into my life after breaking up with me because of her religion. We didn't speak for two years, and that night we were on the phone almost 6 hours.
After a few weeks of talking, I told her I still had feelings for her, and I couldn't just be friends. She didn't understand, and it was at that point I told her I had been in love with her. Then it clicked for her.
Over the next year, we dated, she fell in love with me and she made an attempt to make the relationship work. I even proposed to her. Then she decided to go on a mission.
She broke up with me after a few months, then spent two months trying to convert me. She stopped responding to me, and when she came back, I tried talking to her. She accused me of doing things and treating her in ways I didn't do. She blamed the whole relationship failing on me. She saw nothing wrong with what she did, and just talked down to me.
I couldn't understand why she'd treat me so horrible if she loved me. But she got married less than 6 months after returning.
Since then, I turned myself around. I have a new girlfriend, I've gotten into good shape, and grew out a beard and keep up with myself. I've seen her in passing, and she always gives me an unusual look.
My friends say she give me 'I miss you eyes' but I don't see that, but I'm not too concerned either.
At the same time, I hold great pain, anger and resentment towards her for what she did and I haven't been able to let it go even a year later. I feel she shouldn't be forgiven for how she treated me, but I'm so angry whenever I'm around her because of the pain she brought me.
In this circumstance, is it wrong to not forgive someone?

For the past few years, I was in a relationship with this Mormon girl, and we had a pretty good relationship. We'd have difficulties when she'd doubt our relationship because I wasn't Mormon, but we made it work.
But she had decided to do a mission, and I asked her to marry me. She said she'd say yes when she came home, but she started to push me away. She said she couldn't marry me now because she went through the temple, and she'd stop saying she loved me. She also asked me to see other girls once she left.
I walked out of her place one night because she was making it so hard on me. Later that night, my ex messaged me asking if I'd like to come over and have sex again because she was going to move away soon.
Despite all the issues I was having, I told her I couldn't because I still felt it'd be cheating on my girlfriend, despite everything going on.

Should I have done something with her? Or did I do the right thing?