My (f?)WW is accepting the position that she was applying to. I think that probably does it for this thread. I may or may not start anything in reconciliation. I'm not currently seeking advice, but I will stick around to give advice, since this site has done so much for me.
Without making this specifically about me, is it possible to continue, sustainably in a M with a WS without R?
No it's not.
Say WS is an otherwise good match for you aside from the fact that they had an A. Like the same food and entertainment as you. Wants to raise kids the same way as you. Is trustworthy as it comes to things like finances and time management. Sex is good in both frequency and quality. The WS has apparently stopped the A, and has slowly come to understand the damage that they caused.
However, said WS continues to make suboptimal decisions. Breaking NC, rarely, to have otherwise completely innocuous conversations they tell you about/don't hide. Lying about minor things, unrelated to the A. Something like the price they paid for something. Making friends with AP's close friend. Let's say you are willing to be flexible on basically everything except for an A continuing or a new one starting.
Wouldn't you rather have a spouse that is truly remorseful and understands your needs completely and is working toward or actively is making them a reality?
Is it possible to just suck it up and make it work functionally, even though you cannot fully reconcile due to the WS's actions? How long can you continue in limbo or sitting on the fence as a sort of practical matter? Can you just treat your SO as an exclusive fuckbuddy/roommate/co-parent that just doesn't really care as much about your feelings as their own? It's almost like "I'm in love with you but I don't love you" to reverse the old saying.
No, you shouldn't just suck it up. You speak the fuck up that it is bothering you. You should make yourself perfectly clear on what your needs are, and what goals you have for the new reconciled marriage. If your goals are more than where you are right now, don't just sit around and accept it.
So, there you have it. I would have preferred if the path there wasn't getting progressively less happy, asking for a divorce, having two shitty days that should have been special, having multiple drawn out fights over the same topic to make it clear that I'm not just in a mood. But things are currently headed in a very positive direction.