If your wife went topless on the back deck, it can be quite a tricky situation. You need to approach this delicately. Start by ensuring her privacy and making sure no one else saw. Then, communicate your concerns. Explain that while the back deck may seem private, there could still be unexpected onlookers. You could also discuss any underlying reasons for her behavior. Maybe she was feeling overly comfortable at home and didn't realize the implications. It's all about having an open and understanding conversation without making her feel ashamed or embarrassed.
First, you should quickly cover her up to avoid any inappropriate exposure. Then, have a serious conversation with her about appropriate behavior in public or semi - public areas. It's important to respect the privacy and social norms.
Well, it depends on the situation. If it was an accidental or momentary lapse, gently remind her of the proper way to dress outside. If there were no neighbors around, you could just ask her to be more careful in the future. But if it's a repeated behavior, you might need to have a deeper talk about modesty and respect for others.