Why did Tom want to know about Gatsby in Chapter 6 of "The Great Gatsby"?

Tom was more than interested in how Gatsby knew his wife.

“She has a big dinner party and he won’t know a soul there.” He frowned. “I wonder where in the devil he met Daisy. By God, I may be old-fashioned in my ideas, but women run around too much these days to suit me. They meet all kinds of crazy fish.”