I agree with LH19. And, honestly, if you do it, I see YOU being perfectly fine and much happier after a couple of months, at the latest. You won't believe how good it feels not to be living in a home -- where you're supposed to feel your greatest comfort and most at ease -- that isn't one where you're constantly being given the message that you're just not good enough, that the life you've built isn't good enough, that your W regrets her choices . . .
I lived your marriage, I lived your in-home separation. I did what you are doing in terms of trying and trying to get your WAS to buy in and see value or potential in coming back emotionally into the M. My ex is so similar to yours it is spooky (to me). Yours may stay out of duty or guilt (although I suspect she's just riding it out until you're empty nesters), but she isn't going to give you what YOU want if you two stay under the same roof, because she truly doesn't believe it's possible for her to do it, absent a "spark" she's always going to wait for but never do anything to bring about. She decided a long, long time ago that she wants "more" out of life than what she perceives herself as having. She's playing the long game to get there relative to some, for sure, but, honestly, other than a flurry of guilt when the OM came to light (when, not in-coincidentally, you were at your most detached it seems) and some corresponding pursuit from her, what can you hang your hat on progress-wise? That you're friendlier, like better roommates? I'd argue that's not nearly enough (for you or anyone who wants a life companion) and is really just a reflection of you having worked on yourself enough to keep things calmer and lighter most of the time. And you're into your fourth year of no sex, I believe? No!
I don't see the harm in waiting until after the holidays to make any moves like this, but I would be doing everything I could, now, to detach (you're still on the emotional hook like a citation-worthy large mouth; it just jumps off the page), GAL -- go back to DB 101, like you're just post-bomb drop.
Me: 46 W: 44 Married: 17 Together 21 D13; S10 BD: 03.03.15 (Not attracted to you) Almost 2 years trying, alone, to save marriage Status now: Divorced (effective 06.13.17)