He didn't like it.
She was SUCH a stupid jerk, coming home she said: “You don't know how it feels with thousands and thousands of people standing and cheering your name!”
He said: “But, I DO”
Monroe was reportedly very intelligent.
Apparently DiMaggio was a real jerk in person. Paul Simon said in an interview years ago that he bumped into Mr Coffee at a NYC restaurant and words were said over his name being mention in the song Mrs Robinson. The interaction deflated Simon pretty much because he idolized DiMaggio. Joe had some sort of insecurity about something. That probably was his problem with Monroe’s popularity.