At Glasgow Sheriff Court, Dr Michael Lever, 43, said he has never had his hands round Caroline's neck.
He also claimed he thinks that what his stepson Patrick George saw when he claimed he saw the incident was the couple having sex.
Lever also denied holding a knife to Mrs Lever's neck in a row or to Mr George's neck.
Lever, from Nether Auchendrane, Ayr, told the court he argued with his wife Caroline, throughout their 17 years together and also denied slapping Mr George.
He is accused of assaulting Mrs Lever between March 1993 and January 2001 at properties at Dowanhill Street, Glasgow, accomodation at Law Hospital, Carluke and Sydenham Road, Glasgow. Lever is also accused of assaulting Mr George between July 2001 and March 2004, and his 16-year-old daughter Sophie between January 2008 and January 2010.
He faces a further charge of threatening to kill himself and brandishing a knife and scaring Mrs Lever and Mr George and an allegation of damaging a games console, and denied threatening the family puppy, Lara.
He said a row started between him and his wife as he chopped vegetables and he told her "you're too much" but claimed that when he turned and said this, the knife he was using turned towards his throat and Mrs Lever said "don't threaten me with the knife".
He said Mr George then walked to the door, and Lever told the court: "It could look melodramatic."