Oh wow. That was...dark.
I think what was so startling about it was that the show tried so long to have its cake and eat it too. Rio is a gangbanger with a thriving counterfeit empire, and you don't get to where he is without a few innocent people being removed along the way. But then Manny Montana and Christina Hendricks had crazy off-the-charts chemistry, and they kind of had to tiptoe around the more undesirable implications of his characterization to capitalize on that. This is always who he was, but it took two seasons and change for the show to let him be that.
But of course, it always comes back to FUCKING DEAN. Why would he ever assume that Rio loves Beth? Did he love all the women he cheated on her with? He's justified in not wanting Beth involved with Rio, and not wanting that lifestyle being around his kids, but that was not the way to solve that problem. And he has no idea the damage he did.
As always, Ruby and Stan's relationship is played with such nuance, and the actors sell it so well.
Rio wasn't looking for an alternative until Beth was late with her delivery. That led him to sniffing around Lucy, and then finding out that she was the one who designed the plate, not Beth. If Dean hadn't destroyed the original, Lucy would still be alive.