<human>: Can you give me the gist of the text in a nutshell?

In January I met an amazing man (B) who was in town for training. He was with another friend of mine (A) who I had known since high school. A told me that B was single, B verified this several times. 

We spend a week together and didn't waste time. Texts and snapchats were exchanged near-daily after he left. I flew and visited him in April, and have another trip booked to see him in August. 

I discovered his and his wife's shared Facebook account today. My girlfriends and I spent quite a bit of time researching her after that. 

She seems sweet, a little insecure, and not as attractive/fit. She posts things like, "best friends for life, husband and wife." And talked with a newlywed about ow great it is marrying the right person. 

Do I contact her and inform her that her husband is unfaithful? Do I confront him? Any opinions and experiences are appreciated.
<bot>: Unknowingly had a relationship with a married man. Do I tell his wife? Do I tell him? Help, please!