<human>: I had a great relationship with a girl, and it was my first relationship. She made me happy, she made me laugh, and we had great sex. She liked my weird facial features and my off-humor. It was my first relationship and I didn't understand what I had and I was noticing other girls. For that reason I told her on more than one occasion that I don't know if I wanted to spend the rest of my life with her. We ended it and now I regret it. Before I decided I wanted her back, I had gone on six dates and had no spark with any of them. I wanted to try to get her back after 2 months apart, but I then found out she was happy with another man. I'm finishing undergrad now and I see less and less opportunity to meet girls. I am now scared I will end up like my >25 yr old friends who have no one and are sad. 

How do I ever forgive myself for being so stupid?

Can you succinctly summarize the text in 1-3 sentences?
<bot>: I had a really good relationship that I let go due to the inexperience of it being my first one. I now feel like I will never find anyone as good. How do I forgive myself?