Is it normal that someone flirts with me at school, then never calls or returns

There is a teachers assistant at my school who I see twice a week. She seems to flirt with me, and make comments that would indicate she is jealous about my wife (from whom I am now separated). She gave me her number, however is it normal that she doesn't call me, text me, or email me and rarely returns my texts, and has never invited me to hang out with her outside of school. She admitted to me that she has a boyfriend, but suggested if I stay friends with her I could get her on the rebound if things fall through with her current boyfriend. She told me she would give it up to a guy if he would date her for 2 to 3 months first. She told me about how she is a nymphomaniac and likes to be dominated in bed. I think one time she was trying to pull her shorts to the side to give me a peek at her pussy. I didn't know if I should have looked or if she would have been offended. Do you think she is just trying to use me or toy with my emotions, or there could really be some attraction there?