Ok, I'm watching this for the first time. However, I pretty much know what's going on and what to expect thanks to Reddit.
When watching I'm kind of always looking for the red flags that show these marriages are on the rocks or over.
To me, so far, this is the biggest reaction from Kody that we see where he's not laughing stuff off or finding funny/positive ways to spin his negative thoughts or feelings.
In this episode it becomes glaringly obvious to me that Kody's expectations of moving out to AZ versus what the reality of moving out there has been is so completely opposite of what he wants – its almost shut him down. Then on top of it he has become completely disallusioned with plural marriage and seems almost angry that he's in a plural marriage.
This first part of being out at the pond with Kyle and the comments they show make all the other things come together and show that (to me, with hindsight involved) is where he had decided if he can't have it they way he wants, then he's out. Maybe he hasn't figured out how to get out of certain marriages. But this seems to be the point where subconsciously we finally see that he is going to sabotage or force people's hands so he can have what he wants. He seems just so genuinely angry, frustrated, and jaded with everything.