I'm sorry, but she isn't going to just turn herself in for having an affair. She's going to lie her ass off. She's going to say your husband used his position to forced her to have sex with him. She'll say he threatened to get her fired or worse. And then, just to be a vindictive b**ch, she'll accuse you of threatening her once you found out.
It might be worth considering having your WH coming forward and telling his side first. If she comes forward first, your WH will have to deny unprovable false allegations.
"He who speaks first, speaks the truth."
Edited for typosBH(me)-49, FWW-43,
D-Day #1 - Oct 2007 - On-Line EA leading to a failed rendez-vous
D-Day #2 - Nov 2008 - In person EA caught early.
Away you will go, sailing in a race among the ruins.
If you plan to face tomorrow, do it soon. Gordon Lightfoot