Topic: ex wants me back and 2 weeks later not!

After a relationship of 8years (together since age 19) my ex girlfriend decided to break-up (this is now 1.5 y ago). The passion was gone and she said she had the feeling to have missed something in her life. Something that many people ever face ... I guess we never really had a fight and were best friends. Sexually, we never really let go (mss both as anxiety, with a negative spiral effect). Fairly soon after our relationship she had a flirt and discovered new things, but nothing more than that, she told me (he was not really pretty and she felt just good because he wasn’t pretty she told me literally). We held some contact although it did me some pain, and after 1 year volunteering abroad to make up her mind she came back and told me she had thought of me several months and that I was the one who she wanted children with and become old with. Since 3 months I had new girlfriend and I really had to think about what she said. It hit me harder than expected, because that was what I always wanted to hear, and after month of thinking, I decided to give her a chance but first I wanted to hear if she still thought the same about me. Now she told me she had been confused (common friends with children and a house had her made her mind think she wanted me back) and she wasn’t not at all sure of her decision to want me back. The wound is back open and she has played serious with my feelings, even though she is a lovely and (too) honest girl. I do not want to wait on her, but it still hurts. It seems at this moment difficult to think about marry and have children with someone else. Hopefully one day I'm sure. How do I deal best with this and what would be in hell going on in her head, because she still likes me, but the fear of an unhappy feeling with me frighten her.
I know it’s best to let her go and that I am the one that makes my own decisions, without being played with…
Anyone experience with this kind of stuff (in my position or even in the girls position)?