Thank you for everyone’s responses.
Especially @elletinker700 for such an emotional response.

I’ve asked myself again and again, and I think I don’t have the right intentions of sending it.

I will send him an email, not dated 3 years later, but on a spot. But that day is not today.

And I will write in that email, that I am glad we broke up because it was the right thing to do. And he had brought me this far, and I am grateful for that. And that we are all adults, and he made a choice that he thinks is right for him, and I respect that. And that I have no resentment or any sort towards him anymore.

But that day, is not today. I’m not ready. I am definitely not ready. I have not forgive myself for failing our relationship. And I need to get over myself first.