Yes to all 3!
It's hard to realize though that some would rather not know. We had alot of men @my job that worked/traveled out of state for the majority of their work lives. When I was younger, it was told that one guy in particular (he was much older than me, but I thought alot of him) had a mistress for years in another state.
I "always" wondered if his wife was even suspiciously aware or did she even care??