Need advice for my sitch...

[Greek]

When does it become appropriate to start discussing the R?

Not at all now. She has NO interest in the R. There is nothing to discuss (and you cannot persuade her - which is what you secretly want to do with a R talk). And even if she brings it up, you say, "We should talk about this later. I haven't fully decided where I am with this R right now." Leave her hanging.

If and when your spouse starts to show interest again, what do you do?

Act like you don't notice. Be polite, but don't fully engage. Let her WANT you...not just TEST the water.
Greek