Hmmmmm....

How does someone mistakenly cheat?

Did she think she was having sex with her husband but it turned out to be someone else? Was he wearing a bag on his head? Was it a Uther Pendragon situation where he pretended to be her husband but was really another person?

Did she believe her husband had given her a pass? Was her husband dead and buried and she moved on than he rose from the grave?

This line has sent my imagination flying!

Sounds like she's a cheater. Cheating you and her ex.

Reminds me once I head a guy complaining that his wife was mad about his chronic infidelity. So, pretty much he was cheating, and was going to keep cheating, but didn't want to take responsibly for it. Sometimes cheaters, just don't want to own up.

Great story!