He drove the woman’s BMW to their Baulkham Hills residence and brutally attacked the 39-year-old father, ending his life.

The 51-year-old avoided eye contact with the victims’ family and supporters, who were overcome with emotion in the courtroom after his extreme sentence was announced.

Justice Ian Harrison declared the three murders exceptionally severe, driven by Yoo’s financial hardships and jealousy over the family’s achievements.

“These killings were horrific and violent acts, senselessly cruel and cynical,” the judge stated.

To impress his wife, Yoo fabricated emails, pretending they were from influential individuals.

At the time of his arrest, the reality was stark: Yoo was drowning in debt, owing tens of thousands of dollars, and was behind on his rent.

The victims cannot be identified due to NSW legal restrictions on identifying child victims of crime.