Did I Just Waste My Time?

I feel like I have wasted many years of my life with this man. He wanted to get married, and I wanted to wait. I should have listened to that "gut" feeling I had and held off on tying the knot. But no, my heart was willing and anxious to be with this man til death-do-us-part. At first, the marriage was wonderful. I guess that's called the honeymoon phase. But even after that wore down, we were still alright. We had our daughter and about the time that she was 2 yrs old was possibly when things started going downhill. I spent countless days, months, years of my life being a good wife to him. I look at things now, and I wonder if anything could have changed his cheating on me. He didn't cheat on me in the beginning, so what in the world changed things to make him think it was alright to do this to me? It saddens me to think that I just wasted my time on this marriage, even hoping that things would have worked out for us. Did I waste my precious time?