I think it's even funnier when Joesph joined in. Joesph is just like Dale and nothing like Redcorn.

For being a paranoid conspiracy theorist, Dale is a pretty supportive husband

Now Redcorn might be the father, but Dale is definitely Joseph's Dad.

It's also hilarious that Nancy actually gets insanely jealous when women show interest in Dale.

Aside from saying how this scene let us know how Dale knows of nancys affair, I like to this it also shows how Joseph is more dales son the John .

As badshit crazy Dale is, gotta give the man credit for being a supportive husband and father

thats my boy, monitoring the monitor!

This is so wholesome. Everyone in the family is looking out for each other.

I think he let's it slide because he loves Nancy and Joseph. He knows that in the end he's happiest with her than without her. Plus, there's no other reason to be jealous of redcorn. He has no real friends, he lives in a trailer, no one likes him and many actively dislike him. That's just the beginning, he's honestly the most pathetic character in the show. Dale knows this and realises that in the end he wins.

"She cheated, Hank?

"You always say you want something bigger" he was referring to what he hears her say in the phone calls

Eh...I don't think this counts.

I don't know who I hate more- his wife and John Redcorn for cheating behind his back, or ALL of his friends and neighbors who are aware of it but refuse to tell him.

John Redcorn literally NEVER calls.

Seeing as how John Redcorn had keys to all the locks Dale set up, I'm for certain that Nancy is smart enough to use a different phone that Dale won't monitor.

That's my boy! Monitoring the monitors!

I just realized Nancy was probably talking in code every time she talked to John redcorn and Dale took it as meaning different things than it actually did.

The whole joke is Dale is a conspiracy theorist who can't see the actual lie right infront of his face no matter how obvious.