That IS quite the concern...ANY contracted disease.
It's one of the reasons I eased up on my adventures of multiple inclusions. Infection has become too common anymore, and it scares the hell out of me. We can be careful and responsible regarding ourselves, but that still doesn't guarantee a clean partner.

So, what do we do to find healthy inclusions?..lol...Put an ad out, "Partner wanted. Certificate of clean health a MUST" ?
Hmmmm. (Although I have encountered such ads before, though never replied...lol).

And, yes..the more included, the more complicated it can become, depending on who (of course) and how often.

It is very possible that because you had a wonderful experience with him that one time, that that may be what you are longing for again. That can create some difficulty in the long run, depending on how his wife feels about you and him having your time together without her inclusion.

I hope this can work out for you. Multiple partners can be quite the enjoyment so long as there is communication & understandings at all times.

Good luck with your adventures. I wish you the best.

Shangrala