<human>: Could you distill the essence of the text into 1-3 sentences?

My ex (M22) and I (F20) broke up almost a month and a half ago but my feelings haven't changed at all for him in the slightest. To put a long story short, I fucked up. I know I did, we were trying to fix things in our relationship and I felt like things were falling apart so I got upset and was flirting with a guy who I knew my ex hated. Nothing ever happened between me and this other guy EVER. I never cheated on my ex just to be clear, but I still know that I really messed it up and it is my fault for the relationship to end.

The thing is, he is my best friend. Throughout this entire break up so far he has still be there for me and been supportive about everything that has been going on in my life. I've also been there for him too. It's ridiculously difficult because he is the one person I still love with all my heart and that I trust completely. He understands me and I can even talk to him about how hard this break up is for me and he tries to help me as best he can. He keeps telling me its difficult for him too and he is having a hard time as well.

The trouble is that I know I love attention but I also am terrified of losing something I love. Even though we aren't together and won't be getting back together I am still so scared to lose someone who understands me better than anyone in the entire world. If he found someone else yes I would be hurt and upset but the thing that would hurt the most is knowing I couldn't talk to him like I do now. 

People of Reddit, should I let go of him? How can I let go of someone that means so much to me? I think I have some big deep down issues that are stopping me from moving on, but I'm terrified of not finding anyone that can even compare to what I see in him. I'm at a point where I'm not sure what path to take right now and any advice would help me tremendously.
<bot>: Stuck on my ex boyfriend and terrified about moving on and losing him because he is still my best friend and the one person that is still always there for me when I need him. Need advice.