Purely from an outsider perspective I think there is a whole lot of this being fairly new. Use of terms I am having to re examine right now too.
Poly and mono. If being poly means you have to always have more than one partner no matter what, I might be needing to jump ship again!
And from what I know of mono (many years of practice) I didn't always have only one or even one partner to be considered mono.
You brought up cuckold. And I wonder - you feel pressure to compete because of how you identify it. To avoid it you feel you have to have someone with urgency maybe? Your wife may have a lover now, but who can tell where that will go?
And the regarding your wife's opinion of Bree as Paris and you being back to the farm. Maybe she is feeling a bit insecure right now and feeling like she has nothing to offer in comparison. She tells you what she thinks is going on, but with you so undone right now, maybe you don't know yet if that is the case but its easier to agree than not knowing how you feel right now? Take some time. Go do something with your kids. Address what you will do to manage your depression. Maybe making big decisions right now isn't the best idea?