In love with an old best friend but she married now!!

Okay....I might get in trouble with my current women even posting this but this is something I need to get off my chest before I go crazy. There is a past old friend I grew up with and went to school with since middle school up to high school and we even stayed in the same neighborhood. We were so close we could tell each other anything and we know each other like the back of our hand. On our last week in middle school 8th grade she gave me the sweetest kiss ever on my lips and I can't lie it was amazing. Than high school freshman year kicked in after summer and we grew apart but spoke to each other every now and then. I didn't really look at her in an attractive manner because she was like a sister to me. Fast forward 13 years current and bingo... I was requested on facebook by her and damn she looks amazing. She messaged me and the words she said shocked me....she told me as a kid growing up she always adored me and loved me. Than she go to saying that she think about me all the time and wonder if I do the same. I was puzzled because I only thought of her as a friend and also I'm in a long term relationship of 7 years and two kids. But.....It really warmed my heart and made me wonder what if. Weeks pass and she message me again. This time she wants to know if we can see each other and explained to me that she's in love with me. I refused because it would be disrespectful to my woman. BUT....(there's always a but) I was very VERY tempted due to my relationship having major issues. a year pass and I see a status on facebook that she has gotten married. This is the problem....I realize I am really in love with her and find myself thinking about her quite often. What makes it worse is that she given me the opportunity and I refused which I really regret because I'm now single. I find myself tempted to get at her but that sounds crazy because she's now married. What do I do?