Thirty-eight-year-old Christopher Smeltzer admits he killed his wife, Mara Pappalardo, at their Auburn home last November.
He said he "lost his marbles" when he saw 4-year-old Mason dead with a ribbon around his neck and 7-year-old daughter Mercey's body dangling off a bed. Mercey survived.
Smeltzer was first charged with second-degree murder for the November 2010 killing. Prosecutors later downgraded that to manslaughter.
Pappalardo had been hospitalized previously for mental illness. Prosecutors say she was obsessed with death.
