A bigger picture: A lot of SI's advice given by the "R is possible" crowd is based upon 3 or 4 assumptions, stated next:
A. You can heal from your WS's affair while being in their presence even if they are still wayward.
B. A WS never trusted their AP.
C. Your WS was in love with you when they married you.
D. If your WW doesn't want sex with you then she probably doesn't want sex with anyone. Or she has a block.
That is way, way off the 'R id possible' proposition.
A. You can heal from your WS's affair while being in their presence even if they are still wayward.
By and large, that's absolutely true, but it is not part of why R is possible.
A toxic WS can make their BS's healing impossible, and separation is probably a good choice in those cases. At the same time, some BSes who don't heal may be - and some probably are - trying to shift the blame onto their WS for something they're responsible for.
Betrayal dumps a lot of terrible stuff on the BS, but the BS is the only person who can heal the BS. Sure, if the WS is unremorseful, the sooner the BS dumps the WS, the better.
But most BSes and WSes don't know what's best for them immediately after d-day. So many of us report going back and forth for months after d-day. That means staying in the presence of the WS for most of us.
When signs are ambiguous or vague, the way to a good D/R decision is to start healing ASAP. Jumping into D or R without looking at the actual facts of what is going on leads to big mistakes - it's the difference between 'ready - aim - fire' and 'fire!'.
B. A WS never trusted their AP.
Irrelevant to the 'R is possible' proposition. Healed WSes can restore their trustworthiness to an appropriate level, and a healed BS can chose to trust or not.
C. Your WS was in love with you when they married you.
Irrelevant to the 'R is possible' proposition. Love can grow where it didn't previously exist; love can die where it did. To R, partners need to ask themselves if they can build an M they want starting now and sustain it into the future.
D. If your WW doesn't want sex with you then she probably doesn't want sex with anyone. Or she has a block.
Irrelevant to the R is possible proposition. Besides, if sex is one of the BS's requirements for R, I think the vast majority of us would counsel D'ing any partner who will not agree to meet requirements.
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Some of the assumptions that go into the 'R is possible' proposition are:
1) Both BS and WS are heavily and negatively impacted by infidelity.
2) Both BS and WS have multiple options to choose from.
3) The R/D decision is about the future, not the past. Both partners need to look into their past for indicators of what the future might bring, but the real questions aren't 'What did ____ do to me in the past? The questions that need answering are ones like, 'Am I more likely to live a life I want to live by staying or going?'
Sure, past actions are the best available indicator of future actions, but life has certainly surprised me, and I've had to change my course a lot. Hasn't almost everyone had to change course multiple times in their lives?
4) If both partners agree on what will constitute their post-infidelity M, the partners have the ability to create and maintain that M, even as it changes over time. If they use that ability, R is possible, no?
5) Neither BS nor WS has any obligation to offer R or to work for R.
6) The relationship between WS and ap is what the WS and BS make it to be in their story. Both need to realize that the WS A'ed down with the ap, and the ap A'ed down with WS.
7) R is NOT possible unless both partners get and stay honest, committed to each other, committed to R, and transparent and work together to resolve issues in their lives.
8) 'R is possible' means just that - possible. Not ideal, not s 'should', not a 'must', not guaranteed to succeed or fail, not recommended ... just a possibility that should be considered as part of healing.
That's just off the top of my head.
IOW, the '3 or 4 assumptions' outlined in the quoted text above have virtually nothing to do with the possibility of R.