To be honest, I think it's fair that you lack faith that she'll come. The two of you have very different priorities and one of you has to give. It's all well and good that you want to learn to loosen up, but will you truly be satisfied with a woman who can't give you the quality time you need? Not that she's doing anything wrong....but perhaps she'd be better suited to a guy who's also got a very busy schedule - just as you'd be better suited to a girl who doesn't put you second to everything.
I recall a conversation with a workmate about his failing relationship. His girlfriend complained that she way waaaay down in his list of priorities. And he was quite open about the fact that this was the case. They eventually broke up and he met another girl. This girl was 'The One' and all of a sudden, his personal activities dropped in the list and she because his [URL=https://www.loveforum.net/usertag.php?do=list&action=hash&hash=1]#1[/URL] . He didn't even need to make a conscious choice - it was an instinct based on his love and suitability with her.
In short, I think that you being down on her list of priorities shows that you're not the perfect man for her. Yes, you can try starting again, but that's not really going to change how she feels. And you can pretend to be satisfied with being 3rd or 5th in her list of priorities, but you won't be happy.
I suggest you respect that she needed to end things and let her go. There are more suitable partners out there for both of you.
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.