One year in but a newbie

[MrBond]

"She feels that she has sacrificed everything for them and that is the thanks she gets. I told her I can understand how she feels."

Don't do that. Don't validate bad behavior. And stop offering suggestions. She just wanted to be heard.

"At some point during our discussion my wife must have realized that her dating was now in the open, that I was aware of it and had not reacted in any way towards it. She tried to explain it to me that she was experimenting with online dating."

Tell her that you already knew and that it's made you rethink things. Leave it at that for her to interpret.

"Is she trying to cake eat?"

She's not trying to cake eat per se, but reality is starting to creep up in her.