what does your potential BF need? email, talk on the phone, meet in person? Ask him that, then ask your husband if he's willing to do that, then set it up. Yes, it will be a little awkward. It won't be the last awkward moment you'll experience in your poly life.
Also, ask both guys what their expectations are. Does your potential only need to be assured that your husband is on board and that your not cheating? Or does he want to like or befriend your husband?
Does your husband have veto power in case he doesn't like your potential partner?
early forties, straight.