In the 1978 film "Heaven Can Wait", who is Leo's wife, Julia, having an affair with?

In the 1978 film "Heaven Can Wait", Joe Pendleton (Warren Beatty) is a football quarterback preparing his U.S. team to play in the upcoming National Football League (NFL) season. He is playing for the Los Angeles Rams football team which has been sold to the ruthless millionaire industrialist Leo Farnsworth.

Leo is also (it turns out) the person who is killed by his cheating sometimes foolish wife, Julia Farnsworth (Dyan Cannon). She and Leo's aide, Tony Abbott (Charles Grodin), are the two people who are having an illicit love affair. They murder Leo to get possession of all his money.

This film was publicly been called an upbeat screwball comedy which was made in a smooth and slick way. Critics said that the co-direction by Warren Beatty and Buck Henry was confident. They got performances from the actors that were called slyly humorous. There was no actual threat of anyone being beaten into submission before the idea presented on screen. The screenplay in this instance (by Elaine May with Beatty's participation) takes the curse off the plot's basic sweetness by getting in some nice, mean digs at greed, corporate politics, adultery, professional football and jocks in particular. All the characters at the end of the movie leave it in optimistic way; the best possible thing is happening to the key characters.