Does this sorry letter cut it? Watch
But yeah, nicely done!
i think maybe add a paragraph about what makes you like him and the relationship
I didn't even need to read it to know you deserve forgiveness
I do echo what someone else has said though - I don't think you should have posted it on TSR as it's so personal and not about what any of us think, only him.
I would give it to him, it really is lovely. I don't think you can do any more than that to be honest.
Edit: also I agree with iamtheeggman - put something about him in there, what you love about him maybe, and why you want the relationship to continue and why it means so much to you. To continue with the relationship you might need to rebuild a bit of his confidence which you might have damaged.