Userman
OM being friendly = proof of infidelity.
OM being elusive = proof of infidelity…
See where I am going? You can just as well try to read tea-leaves or the innards of a sacrificial chicken as go on pure gut-feeling and interpreting of vague signals.
Is the gut something to go on? Well… I was in law enforcement AGES ago. I changed career quite some time ago. But I have always worked in analytical jobs involving people and – generally – problems. Gut does have a place, but it’s a terrible control factor. Look at it this way: You would never invest your lives saving on a gut feeling that your favorite sports team will finally win the league this year. Gut can only get you so far and it’s neither infallible nor reliable. LEO training is a lot based on overriding the gut, because gut-feeling and gut-fear is closely related, and gut-fear is what makes officers shoot first and ask later.
I guess the PI came up empty. At best, he gives you some vague report like “Mrs. Userman touched female identified as Mrs. (alleged)OM arm while conversing”. I am guessing you haven’t used the time to set up surveillance, talked to Mr. Rumor or gotten anything in place to move you closer to closure…
I also guess your wife realizes there is thunder in paradise. She realizes there is something wrong and that there is that heavy dark sky in the marital air. That sky might be because she thinks you have discovered her infidelity (if she is cheating). It might be because she realizes she went too far with her friendship with OMW (without cheating). It might be she has no clue as to why there are issues. But it does seem like she knows there is a problem.
It also seems that you are close-to convinced there is an affair going on. I get that. I truly do. That kissing-incident that wasn’t dealt with plus the rumor is more than enough to feed any doubts.
The worst possible outcomes IMHO right now are:
a) You ignore your emotions and soldier on, only to discover a full-blown affair after some months or years.
b) You following your emotions and wrecking a marriage that might have had issues – but not infidelity.
This is what I would do in your shoes:
Find time and space to talk to you wife. Alone, the two of you with no phone, kids or any disturbance.
Ask her if there is something going on. Tell her that you have heard rumors, have been warned by others and have noticed and seen things that support these rumors. Refer to the kissing incident as reason enough for you to take what you have seriously.
There is no need at all to tell her who told you. There is no need to tell her what evidence you have. This isn’t a court of law.
Tell her that if there is something going on or if there was something going on you will discover it. Tell her you have no interest whatsoever of being in a marriage riddled by suspicion and with no trust.
Tell her that if she tells you the truth there is a chance for the marriage – no matter what the truth might be. [I know you have already told us infidelity is a deal-breaker for you. If you tell your wife you need the truth, and that if she has cheated you are automatically filing for the Big D then don’t expect a truthful answer if she has cheated. She has nothing to lose by lying. Give her some hope, after all – you can always stick to your decision that it’s a deal-breaker after a week or two cooling-off period]
Then LISTEN. Hear what she tells you. If she admits then go for the details. Get what you need out of the conversation.
If she tells you there is nothing going on, then let her know that you need a poly so that you can put this behind you. Once again hammer the importance of the truth. Make it clear that in the poly you will ask questions about sexual encounters with others from the day you two married to now. That a failure in the poly will end the marriage but the truth NOW has hope.
The above is something that can be done NOW. It can be done and over within a few hours. It can bring closure to this terrible situation you are in.
But then… maybe the PI has already sent you proof of infidelity.