My biggest regret is not forcing her to quit that job when first found out.
I don't look at it like you'd be "forcing" her to do anything. When I started putting up my boundaries I was told, even my an MC, that I was trying to control her. It took me finding a good IC to realize that wasn't the truth.
You wouldn't "force" her to quit anything. What you would say is I can't force you to do anything. What I can do is control myself and I won't be in a marriage with someone who continues to work and interact with a person that they cheated on me with.
That's a boundary for you, and should be for all of us (I know it is for me).
I tell my wife that. I don't snoop or keep track of her ever. She feels the need to let me know where she is when we're not together as some type of accountability. I really don't care. I can't control where she goes, who she associates with and I tell her that. All I can control is me. She does EVEN ONE THING that violates my marriage boundaries, like even an inappropriate flirt or conversation with another man, then I'm gone forever. It's that simple. I have worth as a person and I won't be treated like that ever again by anyone for even 1 second. I can't control what she does but I darn sure can control what I do. We all can.