Did Mr. Endo have an ulterior motive for inviting the young man to the movie?

(from Short Story International, #59)

Funny, tidy and short. John figures Mr. Endo invited him to the movie about a love triangle because he knows the young man is having an affair with his wife. I like how you don’t know for sure whether John’s just being paranoid or what.
The bio says Yukiko Hirato is/was a pseudonym of Hisako Hasegawa, an author born in Japan and, at the time of this story’s publication (1986) living in the U.S.

Lefty’s Deceiver, “Horizon is Faster”