She has a right to privacy and may have preferred to keep his identity private. He certainly has a right to be there; it is his wife’s office and it is certainly not unusual for a spouse to be at the office for one reason or another. Considering your reaction, I can see why she was trying to diffuse the situation: she probably predicted your reaction and was trying to spare the issue. But, she has no obligation to keep him away from her office on your behalf. Kind of seems like you may need to take a step back and realize the only thing new here is you have a visual of him. Otherwise, you already knew she was married. You already were jealous anyway: this doesn’t change that. She was trying to spare the issue but realized she couldn’t. Her intention was fine, but the delivery wasn’t. Consider it a goof and try to allow an pretty minor error in judgment. This doesn’t have to be a big thing if you can realize that honestly not much is changed except for the visual.