How do you move on after a serious relationship ends when the other person doesn't even want to be friends?

Hi all! People date and break-up all the time. Me and my ex-girlfriend unexpectedly decided to end things after 5 months of serious dating. It's been about a month and a half now since I last saw her. I don't want her back as a dating girlfriend. However, she changed her cell number on me and removed me from facebook as a friend. I think what she did to me was totally cold, mean, unnecessary and childish on her part. I know I hurt her but she hurt me too. I told her I wouldn't "bug" her or "pester" her anymore with texts, e-mails, calls, etc. I even said and wrote down via e-mail and on paper that I was sorry and apologized for any wrong I did to her. She actually told me that I pestered her and her family to try to get her back. She wants me to leave her alone and I respect that. I still don't see why her and can't be friends. I'm totally done with her as a girlfriend but I'd like to stay friends. She was my first love but I didn't realize it until after we broke up. Do these kinds of things happen a lot in a serious break-up situation and eventually p on anyway over time with people staying friends anyway down the road? Her and I have mutual friends together to, which makes it feel kind of awkward. She even asked her friends to remove me from facebook because I was asking questions about her. I basically broke up with her for temporary space and to find myself for about 2 weeks and then I realized later on it was a mistake. I then tried to get her back but she told me she didn't want me back. I accept and understand that. How do you move on after a serious relationship ends when the other person doesn't even want to be friends? Should I just look at this as a hard learning experience and just move on without trying to reconnect with her? Her and I are about 30 years old with college degrees. We're not kids at all. Her and I even talked about marriage and kids together when we dated. It was a very serious dating relationship. Any answers would be appreciated. Thanks!