You are making a mistake

Dear (name),

I hope that you are feeling well, calm and peaceful; because I need to tell you a few important things and I would like you to read this letter till the end, if you don`t mind. I found the courage to write to you because I wanted to not only remember the good moments we had together but also reaffirm that a lot of good things happened between us and that, and they have overtaken by large a few disagreements and other minor setbacks...
I`m writing to tell you that, in my humble opinion, you are making a big mistake. I have already proved how much I love and that I can be a good friend and a devoted partner, and that gives me the right to think that you will not find feelings as beautiful and sublime as mine in any other heart.
The sudden urge to tell you this also allow me to say that you were a very important person in my life and that I still have a great deal of affection for you. I wish I could tell you these things face to face, looking deep in your eyes, seeing your reaction to each one of my words as I reassure you of what you already know: I still care about you.
Actually, I would like to correct the past tense from before: you are a very important person in my life. Please don`t take this letter as an apology; in our case, I don`t think we owe each other an apology. It`s also not a desperate attempt for you to come back to me. In fact, I just want to leave it very clear that I still believe we can be happy together; I still believe in our love and I`m sure all your doubts would vanish if only you reconsidered what I have to offer you in terms of love, care and attention.
I hope you are well aware of how difficult it is for me to tell you these things. I hope you understand that only the love and affection I have for you have made it possible; and that this love is as big as my hope that we will be able to go out together again, holding hands and enjoying all the beauty of life and love.

With a kiss from yours
(signature)