Hearts are hidden behind walls

So-called brothers and friends—you can't trust any of them
You never know when they'll trip you up or stab you in the back!
I'm experiencing it firsthand—the two-faced betrayal of a so-called good friend.
Here's what happened:
I ran into a friend I'm usually close with at the supermarket. He's with my wife, and he actually complains to her ( tattles ), saying I'm out playing arcade games all day and never come home, and that I must be doing really well financially to afford it!
The truth is, I've been going to the arcade lately to play coin pusher games, and my wife already knows about it.
This friend isn't even close with my wife—they just ran into each other by chance—yet he brings this up? What's his angle? Did he think my wife didn't know and would pick a fight with me over it?
My wife mentioned it casually when she got home, and as soon as I heard about it, I could see his malicious intent. I'm heartbroken!
Who goes around badmouthing their friend to their friend's wife? Should I do the same next time I see his wife—tell her he's messing around with women and staying up all night at internet cafés? This is obviously an attempt to stir up conflict between married couples!
Though the incident seems small, it really reveals people's true character.
My wife says I'm overthinking it, but I don't think so.
What do you all think? What kind of friend is this? Am I reading too much into it?