Some suggestions on how to reach a place where you believe you have the truth:
Have a serious conversation – more of a monologue because you want YOUR side to be clear:
You want to reconcile. That is your deepest wish. However you have made two deep discoveries:
First of all, her actions have shaken the very foundation of what you though she was and is. That includes trust. The hour before you learned of the affair you would have trusted her with and for anything and everything. Now – you WANT to trust her but can’t. The only way you see to rebuild that trust is if a) she trusts you (as she displays by being truthful) and b) you can verify what she says. With time, blind trust is replaced by trust-but-verify, and with time the need to verify diminishes.
But for now… You cant trust her fully without verification. That is the work ahead for the first 20 days: Create a base where you start believing you can trust her.
Second: You realized that once she stared the affair you no longer "had" her. At best you shared her with OM. You don’t share your wife. She was lost to you the minute she decided to have the affair. You won’t accept reclaiming a part of her – it’s either all or nothing. Of two evils – losing her would be the lesser than still sharing her.
So, although you WANT to reconcile, WISH to reconcile and will do A LOT to reconcile… it’s totally dependent on you regaining a sense that she is totally yours. You have realized that there is something worse than not having her – because that’s where you are right now – so the threat of this ending in divorce is real.
This isn’t a masculine "possession" thing. It’s more that emotionally a couple "own" each other for emotional, physical and even spiritual needs. When I say "this is MY wife" I might also say "I am HER husband". It goes both ways.
On a general note about marriage: Once we take it as a given we risk not taking care of it. Like if you were tasked with carrying a rare bird’s egg across town you would take more care than if handed a golf-ball. We need to view our marriage as a "gift" from the partner, that can be taken away or broken if we don’t appreciate it and care for it. We can decide "never to divorce", but then we also need to have an action plan so neither reach a stage where we contemplate divorce.
Once you have gotten these two issues over to her (no trust, don’t share) the next stage is to offer an amnesty period.
You want to reconcile, but need the absolute truth to do so. NO MATTER WHAT she shares NOW and in the next days you commit to reconciliation for the next 60 days…
In other words: She shares now that she stops by to do porn-shoots and sniff crack-cocaine (or whatever) every Thursday mornings… You have 59 days to contemplate her truth, her reaction, her actions, your emotions and all that before formally filing (if that is your final decision). The key issue here is to get honesty.
Have her do a timeline. Read it and formulate your questions. Poke at the gaps. Poke at all things that aren’t clear. Get definitions (we made out = what does that mean? Touching, groping…). Get to the level of detail you need.
Try to be strategic: This isn’t something you can sit down after your favorite tv program and deal with in one 6 hour session. Maybe even organize time where you two are alone and have decided to spend the next 2 hours on this. Knowing that won’t suffice and maybe need 2 more hours a few days later.
Focus on factual issues. Emotional issues can muddy things up. Her reason why is something her IC will work out with her. Focus more on how, what and when.
If you can, detach… I have questioned rapists, and a key to that is to detach from the horrible things they did and focus on details and facts rather than the overriding emotions of what horrible people they are doing terrible things.
Mention early on the requirement for a poly, but don’t schedule it right away. Rather – tell her that once she states you have all the answers and you feel either like you have the answers or aren’t going to get the answers you schedule it.
Be very clear on one thing, both to her but especially yourself:
The poly has a purpose. It’s the watershed moment where she passes, and therefore YOU need to acknowledge that you have a base of truth to work from, or she fails where you have to acknowledge that she isn’t a candidate for reconciliation. If you aren’t going to acknowledge either, don’t bother with the poly.