A few thoughts for you to take or leave, some things that really helped me:
Boundaries-- this was huge. AlisonUK was extremely helpful to me in understanding boundaries (and through this I realized that my H and I basically had zero boundaries, or at least zero enforced boundaries). There's a post on my thread from over the summer where Alison talks about boundaries that really helped me to understand the difference between boundaries (that protect me) and trying to change my H's behavior. I also spent a couple of months working explicitly on boundaries with my IC. I think this is critical work and really encourage you to spend some good time understanding what your boundaries are and how to protect/enforce them.
Detaching/GALing-- really, really, really 1000% focus on you. There is really nothing good that can come out of spending your time and energy trying to decode her behavior or her words. Just focus on yourself and what you need to be mentally and physically healthy and strong. Sleep, exercise, self-care. Rinse and repeat.
I really liked this weird youtube video that I ended up listening to over and over-- the daily stoic on "you control how you play"... IDK why this sports metaphor really got me, but it did really help me to focus on what I can control (me) and let go of what I can't control (my H's behavior).
Spend time really understanding what you can and can't live with (this is part of your work on boundaries). If you can't live with not knowing if she's in contact with OM, or isn't in her head back fully committed to the M-- then you need to decide if you want to S. If you are OK not knowing the answers to that right now-- and can focus on yourself and continue to detach, etc.-- then give it all some time.
It is very, very hard. I think many vets here counsel to S until/if the WS is wholly repentant and willing to do whatever it takes to get you back. If that doesn't happen, at least you've started on your healing journey without waiting for them, and you don't get to witness in real time them grieving the end of the A, the loss of the fantasy that represented, all the rest. But if you can handle it, I think there is no real reason to S unless YOU want to.
Me (46) H (42) M:14 T:18, D9 & D11 4/19 - 12/19: series of escalating BDs 9/20 - present: R and piecing