Is This "Normal?" Why Have We Accepted ...

Is this "Normal?" Why have we accepted dysfunction as normal?

"Dear Annie: My husband and I are separated and he moved in with his girlfriend six weeks ago. A few weeks ago, I had to call the girlfriend’s husband in order to pass along some information. "Harris" and I met for dinner and haven’t stopped calling each other since. We occasionally meet for coffee or drinks. There is an attraction that gets stronger each time. I have met Harris’ children and my kids have met him. However, our spouses have no idea we are seeing each other. I realize we are not the ones who broke up the marriages, but I just don’t know whether this is proper. We seem so compatible. Should we continue this relationship at a slow pace to see where it takes us, or must we go our separate ways? — Waiting Patiently"