I'm glad to read that you have good perspective on this situation, and I'm sorry that the best thing for her isn't the best thing for both of you. But here's the most important thing I noticed:
Good for you. You encourage her in the way that is best for her, and you're not holding her back. You are a man. The kind of man more males should try to be.
My respect for you, while high to begin with, is now higher.
I have been destroyed twice in my life by a broken heart. I have also broken bones. I'll take the broken bones any damned day of the week, and twice on Sunday.
And to the haters who are going to make negative comments about this post: go suck a bag of dicks.