Friend may be cheating, wife want’s to know if I know the AP.

I apologize, This is kind of long, but the back story seemed kind of necessary.

So I (61M married) am friends with a couple (54M, 44F) whom I know from work. Let’s call them Fred and Ethel (not their real names of course.) At the time we were working together Fred and I were friendly and eventually became really good friends, doing things outside of work, vacationing, riding Motorcycles, etc. Also at that time Fred was married to Lucy, but clearly unhappy. Wife was really controlling, “managed” all the finances (right into bankruptcy), and when my friend got a second job to help make ends meet, she demanded he give her the paycheck. Our little group of guys that hung together at work chided him and told him to grow a pair and not let her push him around. At this time I also found out that Fred had a habit of “wandering” and currently was seeing some other woman on the side (we’ll call her Fritzy). At around this time Fred met Ethyl working in an adjacent group but in the same area of our building. He shows me some of the texts they’ve been trading. NSFW but I was seeing all this at work. I know, I know, this is getting complicated. He was married, seeing his side piece, and then starts up another relationship. Long story short, Fred gets divorced, stops seeing Fritzy, gets married to Ethel.

As I mentioned before, Fred and I got to be good friends. We vacationed together 2 or 3 summers in a row. Did things together as couples do, but at some point about 4 yrs ago Ethel starts texting/Messaging/Emailing me. Like all the time. I was not comfortable with this, but we always kept it clean and just friendly. Until she didn’t, and started asking me questions like do I ever have feelings for other people (specifically I believe she meant her.) As you can tell by my age, I’m a geezer and although I maintain a very liberal attitude about most things in life, I draw my own personal line at infidelity. I really don’t care what others do and don’t judge them, but I don’t go there. I told her no, I don’t. I’m not like that. She pried a little more and tried to get me to open up some more with what if and what about type questions. I told her I would never do that to a friend and said something I knew would piss her off because her husband says it all the time. “Bros before Hoes.” It’s not something I typically say, but it got the desired affect. She got pissed. Started ranting and raving at me on every form of social media and email, to the point I had to block her. This led to some awkward moments between my friend and I and I don’t know if he ever heard what had happened but he knew something was off and he kind of avoided me for a while. But things got better and cooled off and we started hanging together again.

Cut to this past year, Fred’s away for the weekend with his buds, Ethel starts texting / messaging / emailing me again. She’s pissed because Fred’s not there, she’s sick (just a cold not covid) and he left her at home. I think she’s looking for sympathy, a shoulder to cry on, I should know better but I respond, minimally. This goes on for a day or two and then again she asks what I consider to be an inappropriate question “Do you think we have a “Special” relationship?” WTF?!? I respond with “Hmmm ” as in Hmmm, why are you asking this? or Hmmm, WTF do you mean by that? After not saying anything else she goes scorched earth and starts blowing up my phone with voice mails (at least a dozen) emails (countless), text messages, FB Messenger messages, and god knows what else. I proceed to block her on everything. She finds some other way to message me. I block again. Finally she posts something public on FB that I didn’t see, she tagged me, which evoked the response “WTF?!?” from my friend (her husband). I still don’t know what she said, she took it down right away. So at this point my friend thinks something is going on between us, but doesn’t say anything to me. Out of respect for what might be left of our friendship, I break off all communications with both of them, if they have problems, they need to work it out without my presence. Ethel tried to connect again around Christmas time, but I ignored and deleted everything without reading it.

Now today, I get a couple messages/emails from Ethel (which I ignore), but after the third attempt, finally I read one of them. Evidently she has been snooping Fred’s phone and saw a message from someone named Fritzy that to all intents and purposes, was inappropriate. Says she knows of no one else she can ask, and wants to know if this is someone I know and with whom I may have worked in the past at our former job. I’m probably going to plead ignorance and say no (it’s actually true, I don’t know her) but I’m also inclined to call my friend and let him know she’s snooping his phone. Question is, Should I tell him? I will not blow him in to his wife, and maybe that makes me a jerk, but I also feel guilty for possibly playing a role in his first marriage breaking up. Help!

TL;DR! Friend may be cheating on his current wife with an old fling. Wife wants info, asks me for help. I don’t think I can oblige.