THIS!
I had the same mindset when my ex dumped me. After some time, I did date some women and with one, it was INTENSE both dating/sex wise. What my ex lacked in dating and in the bedroom, she made up for in a huge way and wanted to please me more. Mind blowing no? She WANTED to make things better for me because it MADE her happy. Your ex dumped you for whatever **** reason, and it is **** unless you cheated on her or treated her like crap, but look at it this way:
I spent 5 years trying to please her and make her feel special and I only asked little things of her that would be common sense to the normal human, ie: Clean up after yourself, be more hygienic, be more responsible. Yet, where did it get me?
"I don't love you as much as I used to"
Do you really want a woman who will not stand by you when times get tough? When things don't go her way? When she will not stand up for you?
Look don't hope that the relationship you got dumped from will ever return, because it won't. IF you are meant to be with this woman who dumped you, it will happen eventually that you'll cross paths again. You crossed paths in the first place a certain way did you not?
You are free, you are free to do as you please and mold yourself in the way you see fit. If she comes around again, you can ultimately decide if you want to take her back or not. If she doesn't come back? Her loss.
Do not waste what time you have on this earth over a woman who is flaky in the first place, you deserve better. A special someone will cross you when you least expect it.
This is the opposite for women to men too if you got dumped.