<human>: Provide a brief overview of the text.

So, my girlfriend of 3.5 years and I split up almost 3 weeks ago now. She started dating someone else the day after we broke up and it killed me. I went into a horrible place but I came out of it. I have had time to reflect on our relationship and on what we both did wrong. I started seeing a therapist to help me process and to help me understand where I can change to make myself the best person possible. 

Everyone has been saying no contact is the best option right now and I agree. I know I cant text her or call her that would not help me. I have been thinking about writing her a letter though. I want to write because I feel it is more personal and there is no pressure for her to ever respond. I just feel like I have things I never got to say when we ended our relationship. 

I have the letter written out and my main things are I want to thank her for the time we spent together because it was so meaningful to me, I want to apologize for what I did to get us to that point, and I want to say that I am glad she is happy. Im going to sit on it for a few days and see how I feel about it after some time. I just wonder though is sending something so heartfelt and showing your emotions too selfish? I want to tell her how important our relationship was to me but I also dont want to hurt her by doing so. However I feel like after 3.5 years I should be heard too.
<bot>: Is sending a heartfelt and emotionally open letter to an ex girlfriend ok to do or is it selfish to tell her my inner feelings now?