You are a little jealous but her interactions with this single guy are not good for your marriage. He's clearly on the prowl. If you were invited to whatever bar they're going to so he can pick up women that might be OK, assuming it was cool with you but just her & him, bad plan.
Ask her to invite him to your house for dinner. Then you can sort of stare him down & mark your territory. be civil & gracious but make your actions & body language show you have your eye on him (& her). If she balks at putting you two together, you know you have a problem.
Ask her to invite him to your house for dinner. Then you can sort of stare him down & mark your territory. be civil & gracious but make your actions & body language show you have your eye on him (& her). If she balks at putting you two together, you know you have a problem.