How to get over rebound woes?

Hi, recently got divorced after 15 years. I have a kid. About 6 months ago, while separated, I met a nice person online. She seemed fun. We dated for 4 months. She's a great kisser, fun, and outgoing. She always had fun ideas about places to go and we went to bed and breakfasts, wineries, art galleries, antique shows, clubs, movies and dinners. It happened really fast. She was very nice to me....but, I had a nagging feeling that she was too fun. I wasn't sure how she would be with my daily routine and my kid. We only saw each other once a week or so and I think she wanted more. Once, I saw three empty bottles of wine in her trash and she said she had hosted a book club a few days earlier. I didn't ask about it any more, but I wondered if that was normal. She's a great kisser and we feel like teenagers when we're together. But, it scared me. I told her that I had doubts and wondered if she was the only one who could offer this up. Perhaps there were others that were great, but also fit my needs more. I'm not sure what that would look like, but I don't know as I've not dated in so long. She seemed hurt and said that I should date other people. She said she had invested months into making things special for me and didn't want to end up a year down the road being the transitional woman. She asked me if I could see myself with her in the future and I said I didn't know. Her friends seemed confused too as we had spent time together at events, etc. I needed time to think. This seemed the right thing to do as I read a book that said you shouldn't get serious so soon after a divorce. She was very nice but hurt and said she needed to date other people. I said fine. This also seemed to hurt her feelings. Anyway, that was a month ago and I've tried to date other people. Nobody seems to be as nice, some smoke, some drink too much, and others have let their bodies really go. None kiss as well. I want to see her again. But now she's not the same to me. We went on a date and she is distant and not as much fun. Apparently she met someone else. Was she just putting on a show before? How could she could have really liked me but then meet someone else so fast. How could she have changed so much? I need to make sense of this dating scene. Someone told me that I was on the rebound with her. What does that mean, really? Does that mean that I just thought I was having fun with her?