My husband found out that I was having an affair.
How did your husband find out about your affair?
The truth is that his friend in the office told him.
You shouldn't cheat on your husband. He also shouldn't have to find out about your affair from a coworker. It's best to own up to your mistakes if you want to repair the relationship.
But I don't know if I want to repair the relationship.
If you don't want to continue the relationship with your husband then that's your choice, but it was still wrong of you to have an affair. Your husband doesn't deserve to be cheated on.