<human>: Can you summarize the given text in a few sentences?

We met when she was a senior in high school and I was a a freshman in college. Everything started off fantastic, more than I could have dreamed of, but now 4 years later and after living together for 1+ it's coming to an end. She feels like she'd be lying to herself if she stayed with me because she feels (I do, as well) that our relationship has become the perfect friendship. She also feels like she has to do things on her own in order to fulfil what she feels she has to in life. 

I know this is going to end. We're ironing out the details. I just need help dealing with the loss of my best friend and the girl I really thought I'd marry one day. How did you guys cope with losing someone so close that you spoke with, saw, and felt everyday and now it's all gone? We've discussed that we can't have any contact with each other because it will hurt way too much. How did you guys cope with not worrying about the S/O 24/7? I am scared beyond belief when it's all said and done, I truly am.
<bot>: First serious relationship of 4 years is ending. Trying to cope with no longer having a best friend and someone to care about and speak with and experience everyday.