Marriage vs first love.......?

I am married and love my wife very much.... One time recently we got in a serious fight that caused me to question our marriage.... To the point where i went on facebook and looked up my first love's old email address from 10 years ago when we last saw and heard from each other.. Her email addy still existed and she is now married with a kid according to her profile. It kinda shook me that she was now married... I started feeling kindof sad like "that should have been us". Then coincedentally i saw her a week later at a gas station, i took off before she could recognize me. I know its my own fault for looking her up but why do i have these stupid childhood feeling come back up after 10 years and being married.. am i crazy? I feel like im such a bad husband to my wife now and i do love her so much.