Because of the complexity of the crime it took prosecutors nearly five years to charge Watson, who denied the allegations.
In the end, Watson will serve one year of the 4½ year sentence in his wife's death, thanks to a suspended sentence. Suspended sentences are not unusual for such crimes in Queensland.
Prosecutors accepted the manslaughter plea because Watson -- trained to rescue panicked divers -- failed to fulfill his duties as her "dive buddy," or to even take basic steps to save her life. Prosecutors said Watson failed to give his wife emergency oxygen, inflate her buoyancy vest or to even remove weights from her dive belt. Said prosecutor Brendan Campbell, "He virtually extinguished any chance of her survival."
Watson, who has since remarried, owns the plot where Tina is buried. Thomas told "GMA" he refuses to allow the family to put a marker where Tina lays. There is no headstone to mark her grave and Watson repeatedly took away flowers the family left on her grave.
"She loved life so much and she loved people so much, and I think that's why just about everybody that ever met her loved her," Thomas told "GMA" in the days before the court hearing.
"To us, she is an angel that's watching after us. I just tell her that I love her, and I just keep telling her that I'm going to keep going until I can help her rest and be at peace."
The Associated Press contributed to this report.