I agree with BL. Peter, either a PA is a deal-breaker or it isn't. It cannot be "well today I feel like I would D her if she is in a PA, but tomorrow I might decide to keep the family intact". That is feeling, not a deal-breaker.
However, the one thing I want you to understand is that your only power here is to decide to D her or not D her. A lot of LBS that get cheated on do not understand that. This is what I meant earlier about wanting to tell her "if you are in a PA I will D you". That is not a boundary. It is you trying to scare her straight, so to speak.
Lots of LBSs have fallen into that trap. Hoping the threat of a D (even though the WAS has already stated that is what they want) will make them end the PA. The problem: You have no power to end an A, PA or not. None. SHE has to decide she wants to end it. D, no D, none of that will make her want to end it.
So the choice is simple. Can you get past a PA or not? Also, there is no way for you to get past a PA that is actively going on! So many LBSs on this forum have struggled with this. An unrepentant cheater is not someone you can rebuild a MR with. It just isn't an option. We've had LBSs here whose spouse has cheated, moved out, moved in with the AP, and even gone public as the AP's significant other, and the LBS still will sit there and say "they will wake up and want to come back at some point!" Even to the point of putting meaning into things that have no significance. "My WAS was nice to me today, they must be thinking about coming back!" As if being nice trumps cheating, leaving, moving in and starting a new life with the AP.
I say all of that Peter because I am detecting you trying to DB, you trying to establish a boundary, you trying to have a "conditional deal-breaker", all in the hope that she wakes up one morning and says "Wait, this is not what I want. I want to go back to my marriage to PeterB!" Please understand, nothing you say or do can cause that to come about. She MAY one day wake up like that. It may be in a few months (not likely), or it may be in several years (more likely). The question I have is: when is Peter going to say "screw her, I need to move forward with my life and stop waiting for her!"? That is what I am hoping for, for Peter to realize that DBing is about Peter moving forward with his life, not about Peter saving his marriage.
M(53), W(54),D(19) M-23, T-25 Bomb Drop - Dec.23, 2017 Ring and Piecing since March 2018