That's one of the things I'm dreading with my best friend (the most recent guy I dated and was/am in love with). I want him to be happy, but he was supposed to be happy with ME dang it
In a way, to me, it always felt like if a guy could move on after me, then clearly I wasn't all that important to him. But that's just my warped head. So don't listen to that one.
I'm sorry you're hurting! Just keep telling yourself that Mr. Wrong had to leave for your Mr. Right to come, and Mr. Right will know what a catch you are!
A friend told me this when I had a similar conversation with her, and it's stuck with me: Just because it didn't work out doesn't mean you weren't good enough, or that something was wrong with you. You just were not the right tool for the job. There's nothing wrong with a Philips screwdriver- some jobs just require flat head screwdrivers.