If you're worried about the spouse walking in or catching you where you're not supposed to be you should check out bouncie.com.  It's a little device that plugs into the OBDII port of the wife's vehicle and it has an app that goes with it.  With the app you can see where your spouse's car is at all times.  It costs about $7 a month.

It seems to be a nice price, $67 for the unit and $8 month.  However the current unit uses the AT&T 3G network, which AT&T says is being phased out  Feb 2022.  So you might have to buy another unit (at what price?) in a year.
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That seems to be true for a lot of trackers.  They have attractive unit and monthly prices, but are apparently on the verge of obsolescence in a year.   4G LTE trackers seem to cost about $25-$30/month.  LTE will be around for at least another decade.

Why don't you just put a monitoring APP on her phone while you're at it? I would say no because you're just creating a paper trail to the monitoring system. If she's suspicious, you're just giving her more bread crumbs. That being said, if she is following you she already has more than enough evidence.

Has tracking software built in..came with the car

I took the label off of it.  It doesn't say anything about what it is.  So if that does happen I'll just say I was using it to check the health of the vehicle.

It's her tracking yours!

So you park at the gym and take an Uber to your session with an escort and your wife scans your credit card bill and sees the Uber charge.  LOL

Buy one of those wild life tracking collars, bring it to a local jeweler and ask them to bling it up with gems or even just cubic zirconia. Tell the wife it's a token of your love and esteem and you want her to wear it all the time.  
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Using the bling will keep her calm and distracted while you collar her and you won't have to resort to anesthetic darts.

I suppose you could try and find a cab and pay cash.   Or choose a place to meet a short distance from where your alibi is and walk.  Public transport might be an option as well.   Maybe even the gal will be willing to come pick you up if she has access to wheels.

On Uber you can basically buy yourself a prepaid gift card (Uber Cash) and credit it to your account.  Put $100 or $200 on it occasionally and refill it when your account gets under $10.  Then the charges wouldn't be connected to a specific day.

Hmmm, maybe make it a shock collar. If she's peaking into the hotel window, give her a zap.

I have one. I bought the iTracker brand with a extra battery pack since she changes cars. You can draw a fence on the web browser app around her work / home and when the iTracker moves, it gives me an alert on my phone... "she's on the move!".

Why am I thinking ... Wife to her BFFs: "Of course, I'm suspicious that he's playing around. But no problem! I bought some iTrackers and put them in his car, briefcase, never-used pocket of his winter coat, ... He doesn't suspect a thing!  But as soon as he makes a suspicious move - bam! - I'm on him!"  
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Just sayin' ... if you know the good places to hide the trackers, check to see if you are being tracked, too!

So she just brought me back to her house while he was at work and we fucked away for hours in their bed. All I had to do was keep low in the passenger seat of her car as we pulled up  to her house and into her garage. I forget how she figured out he was tracking her but she definitely knew.

You may need it just in case...

This girl was WAY too smart to get caught. My only problem was her fucking dog, which ran off with some incriminating evidence that had to be retrieved.

Maybe so, but I will bet you that probably just as many ladies do the same thing.  I would also bet you that the percentage of guys that you see that are married that do this is very close to the percentage of guys in the population as a whole that are married and do this ... just that many of them are not as open or honest with you about it.  

stuck in loveless marriages and because of kids, finances, or complicated assets, it would make a divorce the nuclear option.  Taking steps to remain discreet in their hobby activities by knowing they are NOT going to be found out sounds perfectly reasonable to me.  I'm not married, but I have been twice, so I can relate.

I don't know.  I am not married and I don't do any of this.  I find it a bit odd and if I were married I would like to think that I would be completely open and honest with my wife, but who knows for sure how I would behave.  Even I don't know for sure.  None of us do until we are actually in that situation.

Yeah, pretty good, huh.  I will choose to take that as a compliment.  Believe it or not, I am not trying to argue either.  Just trying to understand.