Wedding in a roundabout way

Michelle and Allen have reached a point in their relationship where they want to take the next steps toward marriage. They think it's a good idea to invite their parents to finally meet each other and host a dinner. To everyone's surprise, their parents already know each other very well; they have been cheating on their spouses with each other for months. In this precarious situation, they try to hide their affairs from the children while confronting their partner's lovers with the situation.