Make it two spoken language cliché
Said to the waiter or waitress when you want to order the same thing as someone accompanying you has just ordered.
Waiter: Would you like to drink something? We have fruit juice, soda, wine, and tea. Tom: Give me one orange squash. Mary: Make it two.
Waiter: May I get you anything to drink? Tom: Yes, please. Give me a glass of apple juice. Mary: Apple juice also sounds great to me, so make it two.
The origin of this phrase is not clear.
People tend to like forbidden or illegal things just because they are forbidden or illegal.
He must have believed that stolen fruit is the sweetest, and he, therefore, cheated on his partner.