When a man is married he will usually wear the wedding ring on his left hand.
But when a man moves the wedding ring from his right hand finger to his left hand finger it can mean a number of different things such as he's gay, separated from his wife, divorced or he just prefers to wear the wedding ring on his right hand.
Unless you ask the man himself why he's wearing the wedding ring on his right hand there's no way to know 100 percent why he's wearing the wedding ring on his right hand.
Also sometimes gay and lesbian couples will wear their wedding rings on their right hand fingers instead of on their left hand fingers when married.
So unless you know the person who's wearing the ring then there's no way to know for sure.