I believe Derek already has this realization but is "committed" to what he's doing, the show, etc. He is trying, but, seems lukewarm toward her at best, & may be more frustrated with Katie then he's letting on. Given Katie's behavior, I hope it's Derek who chooses divorce, but,
... it might be Katie because of this. Reject before being rejected. How humiliating it would be for her to be rejected by such an uncool "nerd" (her view of him, not mine).
I could also see them coming to an agreement & saying it's a mutual decision to save face on both sides, with Katie then going on a SM spree trashing Derek.
Actually no matter what happens between them with the (assumed) divorce I could see her doing that.
Reg. Mindy, I thought her wedding look aged her terribly. Their wedding picture looks like she's with her younger brother. She looks much better on Unfiltered & various TH's. I despised Zach throwing his lack of attraction back at her, as if she could do something about it. She shouldn't change herself at all, just accept herself & find someone else accepting (& if they don't move on easily) & she'll be fine.