Why would a person stare (in this situation)?

I went back yesterday for the first time in 2-3 months. And she was there and several times, was staring. Not much of an expression on her face. But she wasn't looking away. I stepped out of sight each time. I had been infatuated with her. I almost know that she was intrigued or attracted to me because she acted like it for a while. I asked her out over a year ago but she had just started seeing someone. I only asked her out because I felt positive she liked me just as well - I have.never asked out another person. She still flirted and checked me out while with the guy. Now she is married to this guy. She gradually stopped noticing me and seemed to have totally gotten over it. Part of that is because I had ignored her since. But I came back yesterday and was wondering why she sat there just staring at me like that. What do you think?