Well, Nicole Kidman is 57 and her next film is essentially softcore porn in the vein of Unfaithful and 91/2 weeks. Your wife should feel great about herself. 

Katrina here

Well, there's what you know and what you don't know about another couple. Especially if you haven't met. They may be complete frauds or wannabes . Or, they could tell you were onto whatever game they were playing. You can even say,"Thirty-nine out of thirty-nine certs agree...."

If I'm actually chatting with someone, I tend to be more open to them. Two examples from house parties:

House Party One:  This man I'm chatting with says that I'm out of his 'league'. I replied,"I thought that was for me to decide ".

House Part Two: Most everyone is naked at this point. We're chatting, about physics, of all things. He explains he realizes he's on the small side. I say," I think your cock is just as hard as any cock that's been inside me making me cum like a freight train." And that turned out to be some very good sex. Great kisser, too.

It's rarely the infidelity that bothers someone as much as the lying.  Then, whatever truth you find, know the reality is ten times more extensive. 

Irrational behavior takes many forms. you have to remember, because it's irrational, it never makes sense.

Once a woman approached me saying, we could just have a one time affair. I replied that I was pretty sure she had at least two affairs going on right now. Never spoke to me again. I was good with that.

As far as you being 'fine' with everything. You already are.  All the questions you posed are ones you already know the answers to . Now, you have to understand it. 

DriverX here.  I grew up on the poor side of the poor side of the tracks. I vowed if I succeeded financially I'd never be the person watching every nickel. To be a gracious host  and be generous.  These days I'm in a very good situation and fortunate that doing a little extra is easy enough. So a fifty-fifty split was a bit unequal. So what ? Not only would I have been grateful for the Champagne earlier, I get to have sex with your wife. That's worth being seen, especially by her, as  generous, even in a small way.

I have found, when it comes to being petty about money, people will rise to the occasion like a Phoenix from the ashes.  Also, when a person is desperate for control, as this guy was, they're the type that always tries to take control with money all under the guise of being 'fair'.  Now, this guy has certainly been in this situation before. If keeping things to the penny mattered, he simply asks the waitress to have separate checks at the start of the meal.  No fuss, no muss. They do it all the time.

One time we met a couple at a Club. We decided to get a hotel and he suggested something of a low end quality. Nothing wrong with that.   Economically, it made sense for them. Yet, I didn't want to harm his ego by saying,"Let me get this". I simply said I have a kajillion hotel points, I can get us a suite at the Hilton and it won't cost either of us a thing. The next few hours were great. A happy play couple really puts out and they were very, very happy. Even Katrina said she could tell the other husband made an extra effort with her that night. Happy (well fucked) wife, happy life.

We have not played separately. Also, if one spouse has a cold, the other spouse is probably a day behind.   
On a related note, we have friends whose profile says “same room, separate room, front seat, back seat, same state, separate state.”