Can you suggest a wise way to handle this awkward social problem?

I am friends with a couple “Fred” and “Wilma.” I began working with Wilma 6 years ago, and then met her husband Fred outside work through Wilma. We’ve all played many sports and participated in many social activities over the years. Fred and Wilma separated a couple months ago, then rapidly signed the divorce papers a couple weeks ago. Wilma didn’t take much of anything of Fred’s. Fred started dating right away, and has a cool hot new girlfriend. Seems awfully soon, but whatever.

Enter another co-worker, Barney. Barney has known Wilma for some years too, and has also hung out with Fred and Wilma in sports leagues and parties outside of work. Barney is now dating Wilma. Seems awfully soon for Wilma, and kind of dumb to date a co-worker, but whatever.

My dilemma is that I hang out with Fred regularly. I’m decent friends with Wilma and Barney, but don’t spend much time with them outside of work. Barney runs a work-sponsored soccer team, on which Fred is a player. Fred is a great player, and can’t make it this week.

I just learned about Wilma and Barney today. Normally I would try to twist Fred’s arm into showing up for soccer, but I don’t know if he knows those two are dating and won’t come, or if it’s because he has something else going on.

It’s only a matter of time before Fred finds out Barney is dating his ex-wife. It was just like 6 weeks or so ago I was helping Fred deal with him not wanting Wilma to leave. Even though Fred is dating, it would be reasonable for him to find Barney to be of low character and untrustworthy. Barney and Fred aren’t close friends, but certainly enjoy grabbing a beer together sometimes.

Do I tell Fred about Wilma and Barney? If I let him find out (maybe it will be a few weeks), he would correctly assume I had known too, and I had not informed him. He could feel somewhat disappointed in me for that. Of all the people, I’m closest to Fred and see him once or twice a week outside of work on average. He may well wish to despise Barney when he learns the truth, and if I leave Fred in the dark and he keeps playing on the soccer team, he may feel like I let him look like an asshole.

I have no knowledge if Barney and Wilma’s relationship helped precipitate Fred and Wilma’s divorce. Probably not.