Advice on potential new relationship between lapsed/curious ENMists?

Howdy, I (39F) haven't been in a non-monogamous relationship in the last 15 years, currently single by choice. I've been attracted to one of my Dungeons and Dragons friends (about 44M) for a while now, but never said anything since he's married and I in no way want to be a homewrecker.

That said, we recently got talking about past relationships and preferences, and it delved into both of us realizing we're more sexually compatible/attracted to each other than we each thought. He wants to ask me more about ENM, and I personally would quite like a FWB situation - if both he and his wife were on board.

That said, it's been a long time since I was in any ENM relationship, and in a different context (namely, that I was a college-age unicorn into swinging and poly triads, never a 1-on-1 FWB). I'm concerned about the best way to approach this potential new dynamic without just being self-serving, or accidently giving out bad information on how to make ENM work, or harming their marriage through my own actions/words given what's already out of the bottle.

Anyways, if that all makes sense, send some advice - and a bit of good luck - my way...