Posh wank eh?, well if that's what its called yes bin there shagged my right hand;. Done it with a rubber a few tines sometimes to see how a particular type feels before real live use and sometimes it can make a mess so contains the fallout. Especially if you err, get turned on by someone other then your partner wife etc by accident.
Now that means if you don't use them for normal nookie with the other half then you have had to go out and by them which in this instance does seem a bit odd.
So where does that leave us?
If, his having a bit on the side and a 24 is she Y/O?, fine with a 40 odd year old its not beyond reason then he's being absolutely careless leaving the detritus of that around he would have had to get rid of the filled bit so where did that go and why didn't the wrapper go with it?.
Mind you he's got the opportunities and you say he deals with proprieties somewhere to go for this liaison perhaps or else it would have to be her place or the car or a hotel ?.
It might be that he found them in his cab after all he would be running couples back from a night out the man intent to have his wicked way with his girl so he would be "armed" and they could just fall from a trouser pocket no problem. If be pulled out his wallet to pay they could have come out noticed with him being so excited at having his end away hew was in a tearing hurry to lave the taxi,. Your OH finds the packet thinks haven't used one of these for years, might start playing, jus saying;!
So perhaps the latter? I doubt someone would leave a used wrapper in a car unless that was pulled out of a pocket by accident ?.
I'd wait till he gets home and explain he if there's was a real reason will come out with that right away if there was a dubious reason you should be able to tell?. Then trust that gut instinct that women seem to posses in abundance.
Ask to if you can have a look at the messaging on his phone if he's got nowt to hide then he will let you see that course if you call him at work then he's got plenty of time to make or dream up excuses and clear the phone out. He if he has been on the cheat may well have another phone somewhere?.
Me?, I'd think its was more than likely innocent or else he's bloody stupid leaving that evidence around after he's done the deed with another.
If he did find a used wrapper in the car what would have have done with it or if you were a driver what would you have done with it chucked it out the window or just pocket it after all you wouldn't want a lady passenger or any other seeing that in the back of your cab eh guv;!