Why do people advertise that they're in a relationship?

People on Facebook put their business out there. One person showed they’re married. Now people are shocked because they didn’t see it coming. No photos of the person or wedding. His name is not even mentioned.

Second situation another posted they were in a relationship. Again they posted that info so of course people are wondering with who. Doesn’t indicate with who at all or no photo. This is someone who post every second.