They only did it the one time. Jill told me she didn’t know why I always commented favorably about Mike in bed; she didn’t find him any great shakes. She went on to other guys and I tried not to receive her reports.

And maybe my lack of enthusiasm for her afterstories is what ended our friendship. Or maybe it was her low self-esteem. I’ve watched her for a long time, and as crazy as it sounds, it’s like she comes to despise anyone who loves her because she’s so convinced that she’s unlovable. The way she sees it, if I like her, then that’s proof that I’m untrustworthy or foolish.

Anyway, our relationship cooled even while she stayed married to Jack. And ten years later, after they finally split, the severance was total.

During that decade I had no reason to think Jill altered her habits. I heard about her affairs early in those years, and after we stopped talking as much, the words I received came from Jack. Their marriage was not open, and I could tell that nothing had changed.

I also knew that Jill had spoken to Jack about Mike. Jack never asked, but Jill volunteered the libels. She told Jack that Mike had come on to her. She reported more than one occasion when she had resisted Mike’s lusty advances.

The way Jack told it to me, Mike had betrayed him. Jack said he used to feel close to Mike – like Mike was the brother Jack never had – “until he came on to my woman.”

Awkward doesn’t describe how I felt. But I had been Jill’s friend; there was no reason to “out” her even though we were estranged. I let Jack’s comments be.

Until the lunch.

Ten years after Mike and I divorced, the excrement hit the ventilation system in the Jack-and-Jill household. Jill left her home computer open while she ran some errands. Jack’s attention was grabbed when he passed their study door and he stepped closer to see the screen. He was slapped in the face (more like batted on the head) when he read the sexy exchange between Jill and some Facebook friend.

He confronted Jill as soon as she returned home. Immediately she confessed that she’d been straying. I thought that was refreshing, when I heard about it. Was she open because she’d come to some epiphany or moment of change? Was she hoping to provoke a declaration or new passion from Jack? I don’t know. He acted reasonable and understanding. He told her he wouldn’t stand in her way if she thought she could be happier with someone else. But he accepted her momentary honesty like it was his own, and it made him assume she was telling the truth in general. So he believed her when she asserted that this was the first time. And she later told a mutual acquaintance that he disappointed her with his reasonableness.

Jack was tolerant but decided not to wear the horns. He asked Jill to move out when she told him she was going to continue to have her own after-work relationships. He asked for a divorce when he realized that he couldn’t agree to the sort of disconnected marriage she said she’d accept.

And so it was. The final decree was about to be issued when Adam came home on winter break and Jack joined us for lunch. Jack had always been more like an uncle to Adam than a cousin. They even look alike.

We tried to make the meal celebratory. Adam was doing well at college. Jack was not happy about the divorce but was trying to view it as the first step in a new life chapter. I had white wine. Jack drank bourbon.

We were most of the way through the meal when Jack narrated the Mike story again. I guess it was supposed to be some sort of avuncular reminiscence about friendship or something, but when he got to the “I used to think of him as my brother until he came on to my woman” line, I had to speak. Jack was talking about Adam’s father.

“I’m sorry, Jack,” I said, “but that’s not the way it went down. Mike and Jill did do the deed, but it wasn’t just his idea. And he wasn’t the married one. I’m sorry, buddy. I didn’t want to tell you. But I can’t let this lie about Mike go on.”

Jack believed me. He asked Jill about the story that night. Her reaction was profound anger at me. “I can’t believe she told you,” he reported Jill saying. “She was supposed to be my friend. I’m tempted to send her an angry email.”

Of course she hasn’t. I’d welcome a chance to speak to Jill about the incident. I know why I told, and I was justified. What I want to know is why she created that lie.