Salamun Alaykum from Turkey,
Exposing one's sin would not be good unless that person made it clear that he wouldn't repent the sin and go on doing it publicly. You know we muslims are supposed to be like the nightfall in hiding our borthers' or sisters' wrongdoings or sins. I know a lot lof people born muslims, who think as long as two sides do it at will, they think adultery is not a bad thing and so does not have to be considered a sin. However, commiting adultery is already sin and if one side has no consent to doing it, then it is a case of rape. I know of many people who say "I'm not gossiping about my brother or siter. I'm just telling the truth" However, they are ignorant of the fact that "gıybat", as it is mentioned in the Qoran, is whatever you are talking behind your bother's or siter's back. You are alreayd sinning. If you are talking something untrue behing their back, this time you are both gosiping (gıybat) and slandering, which is even worse. Wassalam.