Is my wifes new love the reason she thinks we had such a terrible marriage?

My wife of 10 years says I have always been angry, at the world. I never hit her or the kids and was a bit angry I agree. She met someone at work and he showed alot of interest. She didnt stay with him or anything she just started acting like everything in our marriage was no good, and that I should have tried more. We had a lot of very good times. We made a life with each other out of those good times. We baught a new house not even 2 years ago, and she admits that at that time of our life she was happy. Now all of a sudden she says for 10 years I have been angry and didnt treat her with love. I did the best I could i believe, yes I did some things wrong. She says its a little too late for me to change and that I should have tried to change for her before instead of for me now that she has left. The problem is she is steadily seeing this man, and I didnt even know she was feeling like leaving me until about 4 weeks ago and she moved out about 1and a half weeks ago.