Hi! My first thought about this, is that in my case when I do something that has been hurtful, I need to make amends. For me, amends is apologizing for what I've done and saying I was wrong. But the most important thing is that I do it without an alterior motive. As Ozzy said, if she wants to contact you after that that is her chioce. The other thing I have done is to write on the envelope, "An apology" where my address would go. That way they know it's not something else. Then I can let it go, knowing that I cleaned my side of the street and did all I could.
The other thing I thought was if you don't know why you cheated in the first place, you might want to figure that out. There might be something there that needs to be addressed. Good luck to you! Annie