Cheating Wife?

[DenverBroncosJM]

OK I need some advice..(no its not my wife)

My wife and I are friends with another couple and we have been for years. We camp together, vacation together etc.

We (my wife and I) have noticed a difference in the way lets call her Sarah is acting recently (past 3 months) she goes out approx. 4 nights a week now and stays out way past 2:00 AM. My wife and I discussed it briefly a month or so ago about how that's a drastic change in how she normally is, she was dressing different the whole nine yards. I told my wife then she is having an affair but she blew it off and said no she would never do that. The problem is her husband doesn't question anything hes the kinda guy if she is happy he is happy so I'm not sure he is picking up on the nuisances but they are obvious.

Well Sarah came over our house the other night and she explained to my wife (after a lot of wine and "excusing herself to take a call") that she has been out all these late nights with another man. I was in the den so I did not hear the conversation etc.

So my wife tells me all of this the next day and then tells me that I cannot tell the husband because she is the only one that knows. So I have been racking my brain on how to let this guy know. They have two kids (One she had from a previous relationship and the father was a dead beat so he adopted the kid legally) together and I feel like after all he has done for her AND her family (loans them money when they are in a tight spot...a lot) its a real sh*tty way to treat him.

I have to let this guy know...so here is the idea I had send a letter addressed to him to someone out of state have them drop it in the mail so it has a different post office tag on it and just have it say something along the lines of "You should hire a PI to follow Sarah" or hell something.

Any thoughts or suggestions?