let me add a few

"It was nice talking to you after all these years. I regret the way I did it to you. I'm really sorry. I find some confort in knowing you move on with your life with peace.
I was young and stupid, did not know what I did meant to other people.
Enjoy and send my greetings to your wife and children."

If you had to, you could just say the words I added and drop all your own words !