On the one hand, I do think it is considerate of you to think about being "good hosts".
And the rewards for your consideration are above and beyond what most "hosts" are seeking, so the topic is certainly worthy of concern.
But the flip side of the coin is that you have already in your mind "isolated" the gentleman by feeling you need to consider him in any manner varying from the norm.
I have been in and around the lifestyle for a good number of years. Long enough to remember having made some remarks along the way [to folks I really liked and admired, both male and female] that I am now embarassed recollecting the remarks. I meant them as compliments, praise, even flattery. I now recognize just how patronizing the so-called compliments must have sounded to those I had bestowed them upon.
The proper "turn of a phrase" CAN make all the difference in the world though, it's just a matter of taking the time [as you are wanting to do] to think before you speak.
I am old enough that we frequently get emails saying "Do you like younger guys? I LOVE older women!"
Here's the deal: I recognize that the email is meant as to be a compliment. But hey, I can read the ages - I see he's younger, I know I'm older - so the isolation of that fact alone is not necessary.
What would really come across as a compliment? An email that said something along the lines of "I am weary of the lack of depth evident in most GIRLS and seek the far more sensual advantage of being with a WOMAN."
Both emails mean the same thing, but which do you think has a higher chance to be answered?
I am NOT however suggesting you spend the day constructing the correct turnings of every phrase and memorizing them.
You have already gone through the process of contact, and agreed upon mutual attraction. He is aware of the "numbers" as well. If it were a negative feature, I don't believe he'd be married to someone of "your age group".
The evenings success is NOT going to hinge on where was everyone when man first walked on the moon, or who was alive when Kennedy was shot?
Relax! Accept the guy, appreciate who he is [without mentally stamping a number on his forehead] and go with the flow. He'll know how to deal with it quite easily, or he wouldn't be where he is. You have things in common, use them as your foundation.
If he needs a glass of prune juice, he'll ask for it!
