This is common and happens because when you meet someone who acts interested in you, it's not something you expect. In college, I had a guy I would see on campus that flirted with me, and I would stop and flirt with him too. After a couple of weeks, we were talking and he mentioned his wife. What? I was waiting for him to ask me out and I was surprised and hurt. Of course, I stopped going past him or talking with him but I was mad. Some people will get attention in any way they can at the expense of another person. I'm sorry you had such a bad experience.