If you tell someone that an action will automatically and unequivocally lead to a certain result then they have no incentive to confess to that action. If your wife knows infidelity in any way or form will lead to divorce… she has no reason to confess to anything that might have happened.
Let me preface the rest of my comments with this:
Situations like the one you describe are some of the situations that bring out possibly the worst advice on this forum (probably mine included). To be a valid member here you need to have experienced infidelity – so each and every one of us has probably been in the spot where we wonder why we didn’t see all the red flags in OUR relationships. For US the nudes are near bullet-proof indicators of infidelity, the talking with the two men, the phone-number similarity… As one poster wrote a few years ago: For hammers everything is a nail. Although I care deeply for this site I’m in no rush to increase our membership. Therefore I won’t insist your wife is cheating – but she might be.
I’m a former cop and in my training some important investigative guidelines were burned into my brain:
Investigate to discover what’s going on – not to confirm a foregone conclusion.
In your situation: Investigate the leads you have to discover what they are about. They might be about infidelity, they might be totally benign, they might be that she has a gambling issue, they might be that she’s into stamp-collecting or whatever… Way too often we get posters that only investigate infidelity. Do that and you will be wondering if the convo with her best friend on the VAR where they talk about going to the Mall is code about meeting men for sex. Investigate for the truth.
If – after reasonable effort and reasonable time – you find nothing then maybe it’s because there is nothing going on.
I think the poly is not appropriate right now. Part of the poly’s efficiency is a level of fear from the person being questioned. When we recommend the poly it’s usually as a tool to know if a wayward spouse is honest in what has been revealed about a know affair. If used correctly it’s the stage where the betrayed spouse can reach a stage where he/she might be confident in committing a bit more to reconciling because they can have a sense of knowing the key issues about the affair. The WS knows that if they fail the BS will most likely give up and accept that divorce is the only viable path, and this causes stress and fear that encourages truth. It’s a well-accepted statement on this site that learning of 2 affairs early-on in the R process is better than learning of an untold kiss a year down the road. Trickle-truth probably is the main marriage-killer.
I would suggest the following:
If she’s having an affair, it requires communications. Knowing your stance on infidelity she won’t be talking to anyone in the home, but rather in a place she feels safe to do so. That’s the car. A strategically placed VAR will quickly give you a strong indication of if something is going on.
Affairs require money. Do you have access to online accounts? Is there some unusual financial transactions? Like if she mainly uses a card but when going out she takes out cash – and that maybe a higher amount than would be needed for a salad and her drinks? Would the amount cover an extra plate and some drinks, or a motel-room? Or the opposite: does she go out with her BFF but there are NO transactions – as if someone is paying for the meal and drinks?
(Like if her AP is the bartender at that bar then he probably might comp her for the drinks)
What about purchases leading up to going out? Spend money on lingerie, or more "personalized" beauty treatments? (Like having her eyebrows plucked or her legs waxed are not really big flags IMHO, but maybe a full Brazilian would raise a flag…). Spend money at a chemist (thinking condoms…)?
Does she use ATM’s at sites you two don’t frequent? She’s not likely to meet up with AP at places she might show up with you a week later, or where she might run into joint friends. If she’s having an affair and meeting her lover it will be Eastside rather than your Westside.
Note the odometer on her vehicle. Again – not likely to pee in her home-garden. If she says she went to that bar (5 miles away) but her vehicle was driven 50 miles…
When she comes home does she look/smell freshly showered? Does she immediately take a shower coming home?
If you can – before she leaves – check her bag if she has extra undies. Or the laundry once home if there are two freshly placed in the laundry.
What about phone-records? Once again: infidelity requires communications. Now – it’s to be expected that there is a flurry of calls between friends when arranging a meet-up, but you should be able to recognize those numbers. Is there an unknown one that is called in-route or has been dialed several days previously?
If you have a wireless network and have basic knowledge of routers you can probably monitor what sites are being frequented. Won’t give you details, but you can possibly see that she’s using some form unknown to you to communicate with possible OM.
I would suggest you look at the above ideas and do some research. Frankly – only hearing a convo on the VAR would "prove" infidelity per se, and most of the above should either help you realize there is more that needs to be investigated OR there is nothing going on. But start as many of the above as possible to get a good base to work from.
Once the VAR is in place and you have scanned her phone-records…
I would confront her along the lines Serpico suggested.
A conversation where you describe your concerns about the nudes. You can add to that the big risk she’s taking in being so careless about them. The Internet is full of pics of women that had no intention of sharing their bodies. Don’t know if you have kids, but woodsraier jr. would have a hell of a time if the school-bully were to pull up pics found on amateurmilfsdotcom of Mrs. Woodraiser.
Add her behaviors and be open about your concerns. Remember that she THINKS and KNOWS that if she confesses you will divorce. Give her a one-time offer: If she tells you the truth NOW then no matter what it is you will give the marriage a try, or will not commit to divorce for 90 days. (It’s an empty offer since either one of you can file for no reason at any time, but it does give her an incentive to come clean).
Finally: IF she has cheated she has cheated. Denying it and keeping it a secret because she fears divorce will be like a boil that keeps growing. It will eventually burst, only maybe when her conscience cant carry the secret after 15 years, or when her then-worst enemy but now-best friend blurts it out to you. It’s better ALL DAY to get the truth NOW.