Michael Lever, 43, attacked Caroline Lever when she was pregnant with their second child and strangled her over a table.
The assault was seen by Mrs Lever's son, Patrick George, now 20, who claimed he thought his mother was going to be killed.
Lever, who has five children with his estranged wife, also slapped Mr George for taking a book without permission and threw a can of beer at his daughter after an argument.
He denied the charges but a jury at Glasgow Sheriff Court found him guilty of assaulting Mrs Lever at hospital accommodation at Law Hospital, Carluke, while she was pregnant.
The doctor, from Nether Auchendrane, Ayr, was convicted of an assault on Mr George between July 2001 and March 2004, and his 16-year-old daughter Sophie between January 2008 and January 2010. He was also found guilty of a breach of the peace by holding a knife to his throat and brandishing the blade, scaring Mrs Lever and Mrs George.
Mrs Lever, 42, told the court Lever moved in to her flat with her and her son, at Dowanhill Street within a matter of months of them going out. She described him as "very much the disciplinarian" with regards to her son Mr George, now 20.
In his evidence Mr George told the court: "I went out to see what was going on and I found my mum on the table with Michael standing over her. He was on top of her... he was strangling her."
Sheriff Sam Cathcart deferred sentence until next month and Lever was released on bail.