How do I get past my resentment of my wife?

I know this is long but please consider helping me if you can. We've had some problems over the last year. I finished my advanced degree and prepared to enter a new career. Around this time I found out she had carried on a flirtation with a man at her work. She was also in the habit of making very hurtful comments that insulted me as a man. This culminated in the week I found out about the flirtation from her coworkers cracking jokes about it at a party. I swear if someone had walked up to me at the party and yanked my pants down I would have been less humiliated. Later that week I caught her behaving in a forward manner with a guy delivering something to our home. She was very blatant about it and let him get away with some insulting behavior and encouraged him. I asked her about it later and she said that he was her type of man. This really hit me. I felt like over time she had lost respect for me. I also felt that I was the one who always tried to fix everything and that I was walking on eggshells around her. I worried so much she would leave me or that I was a bad husband. It seemed like everywhere I looked there was some article or tv talk show advising that men failed to be good husbands today and I worried a lot. When I talked to family or friends they seemed to always ask if I was showing her romance or sensitivity, and then advised me to take her out to dinner "once in a while." But I took her out about once a week on average and brought her flowers or a card all the time. For her birthday I bought her a great gift but she said she was disappointed and hoped I would do better next year. I guess I realized that I couldn't fix things and that trying to talk to her seriously about it just made things worse. So a few weeks ago I stopped trying. I still work hard for us and do my share at the house and fix things. But I don't ask her to talk with me about the relationship. If she gets mad about something or complains, which she did a lot, I just ignored it. I basically started to live my own life and not worry so much about her and her happiness because I felt like I couldn't make her happy. Since I started this it seems like she has done a 180 and works hard to talk with me and make me happy. She complains now and then but overall she avoids doing that. I think that things are better between us and she is trying now. But how do I get past the resentment I still feel over how she acted? When will I feel better about us and begin to trust her again?