My Cousin’s Wife With Another Man

What should I do?  Should I confront my cousin’s wife, tell my cousin, or keep my mouth shut?

Today I was leaving the parking lot of BJ’s at 1PM.  My attention was drawn to a black SUV with an opened door.  At first I thought that someone accidentally left it open or that someone had broken into it because I didn’t see anyone on the outside putting in packages.  So I slowed down.  Then I was able to see that there were two people in the front seats of the SUV kissing and caressing. 40ish looking.  What the f***?  It surprised me that they weren’t teenagers and that they were making out in broad daylight.  A few things went through my mind.  One being that they must not be married.  There’s a reason why they were doing that in the parking lot.  The SUV looked familiar and then I recognized that it was my cousin’s wife with another man.  What the hell!  I was so upset that I almost hit a car.  I literally started talking to myself out loud.  Is she f****** crazy?  I called my wife and she told me to stay out of it.  My cousin and I are close like brothers and I was the best man at his wedding about seven years ago.  My dilemma is, what is the right thing to do?  I don’t want to get in the middle of it, but I think my cousin should know, or maybe he already knows.  He works two jobs to support his family (including two sons), and they recently built a beautiful new home in the suburbs.  I don’t want to get involved because they could possibly break up.  It isn’t for me to judge, but I strongly feel like I am doing something wrong by not telling my cousin.

image- ReneS