I think this is a good idea, OP. You don't need to make a massive deal of it, just say, I just want to check before we arrange to meet that your wife knows and is fine with it? It's just something I am sensitive about - I would hate to cause a problem in a friend's marriage.
If he is innocent, he will understand and say, yes of course she is fine with it, she isn't the jealous type. Or, I hadn't mentioned it but am happy to, something like that.
If he reacts angrily or suddenly goes quiet you will know he isn't the good friend you hope he is.
He may even use it to test the waters for an affair, and start telling you about how she is a jealous harridan who doesn't understand him. You seem an intelligent woman of the world, so I am sure you will recognise this for what it is if it happens.
People on here can be a bit funny about male/female friendships. The only person I have ever met with quite the same views on real life, was my controlling ex, who was convinced I was shagging every man of my acquaintance (and half the women too) every hour, on the hour, until it got to the point I wished I had been!
Each to their own in relationships, as long as it's fair and both partners abide by the same rules.
But it is very possible for straight (and bi) men and women to have opposite sex friends, even married ones, with no suspicion of ill intent.
I also think (perhaps more complicatedly) that when in a committed relationship, you may have some friends who you do acknowledge are attractive and you think, if you were single, they would definitely be your type. But you aren't, or they aren't, so you just stop as friends.
I have had married male friends in the past ask me if I think we would be together if they were single. And I just shrug it off and say, well, you are not, and I am a nightmare in relationships anyway, ask all my exes!
And with those friends I am careful, as stated above, to ensure their wives know of my existence and any social plans we have. And I wouldn't, say, go on an overnight trip with those friends unless the kids were going too....
Affairs don't happen without the express intention of both parties. To put it crudely, you don't trip, fall, and land on someone's dick. So as long as you know you won't shag a married man, which you seem very clear on, you are fine, OP!