HBH, if your M can be saved, will you desire to remain polyamorous?
If you decide that maybe you don't want to have other intimate Rs, are you willing to accept that your W may wish it, and that would be OK with you?
Trust can easily be broken. What makes trust in a poly M different than trust in a non-poly M? Nothing.
I'm saying only that trust is trust, and you broke trust. At least, according to your W.
There are certainly inherent risks in a poly M and it can often be a test of trust.
Here's where the questions begin in that regard.
These are slightly rhetorical. In entering the poly-M, did your W not understand that there are risks? In breaking trust, from a strictly objective basis, in one single incident, is that enough of a reason for your W to be unsure she wants to remain M? Was there an agreement about the need for immediate disclosure regarding the poly-pact discussed?
I agree a DB coach is always a good idea, and agree that if you can, it will be helpful for you.
That said, if this is an objective issue of your W using one (certainly valid) break in trust as a reason to end the M, then I would submit that it is very likely your W has other things going on in her mind that is causing her to question the M.
Detach specifically relating your W. You will have to decide whether you wish to remain in an open M.
She is also in an open M with some added twists, but the two of you certainly have things in common and her M has been opened and closed a few times, depending on certain circumstances. Their M has been open on and off over 10 years, I believe.
Stay in the home and continue to keep things pleasant with your W and also be sure to continue to co-parent and comm regarding the kids as well as financial.
Yes, don't 180 by not doing things that are positive. No longer helping around the home would not be positive, keep doing housework.
What you should be focusing on is working on trust, which may be MUCH MORE than just broken trust in the "incident". Generally (and again, I want to assert this is OBJECTIVELY; even considering the assumed severity of risk of the incident) trust doesn't end with just one incident. It is broken over time. There is likely other things around trust that might be an issue.
Can you think of anything else that might have reduced your W's trust in you?
You do want to look at 180s that can help rebuild trust, at the very least.