Why would my wife say this to me?

Last year she had an extended flirtation with a co-worker that I found out about through her colleagues. They told me. She also was involved in flirting with various men she came across, sort of one-time things, including once she showed too much of herself to another man. Around this time she regularly started getting down on me, insults, "jokes" and so on to put me down as a man and a provider. We worked on things a lot and I was usually the one who wanted to talk things over, which bothered me and made me feel like I'm the woman in some ways since women usually want these talks and she couldn't care less. We did get better and she has stopped insulting me and we have incidentally moved away from her old job. Well over time she began to see my side but held to her view that I overreacted, that she was down and had low self esteem. She said she thought about the other guy but nothing more and it was nothing like cheating, though she's never accepted that from me (a girl looks at me and I'm in trouble, always). She said her comments are hard to understand but were about her and not me, and the jokes show I am too sensitive. She said showing herself to another man was a mistake but she's sorry. I began to accept things as getting better and try not to be so hard on her. But when we were getting ready for bed last night she had tears in her eyes and said to me, "I can't believe that I broke your heart!" I know she's trying to be a good wife but why would she suddenly admit to such a thing when all along she has denied doing wrong? Why would she say this to me?