In Chapter 6 of "The Great Gatsby," how does Tom feel about women who "run around too much"? Why is that ironic?

In Chapter 6, Tom says, "By God, I may be old-fashioned in my ideas but women run around too much these days to suit me".  He is suspicious about how Gatsby met Daisy, and, "perturbed at Daisy's running around alone", is sure to accompany her to his next party.

Tom's comment is ironic because it exposes so blatantly the double standard he holds.  In Chapter 1, he made a similar comment about Jordan Baker.  At the time, Tom had a mistress who had been calling the house repeatedly during Nick and Jordan's visit with Tom and Daisy.  Everyone knew about her, and just minutes before his observation about Jordan, Tom was upstairs arguing with Daisy about his mistress, and Jordan was eagerly trying to eavesdrop, salaciously hoping to get the sordid details of his latest infidelity. 

Apparently Tom had always considered it acceptable for him to "run around" as much as he wants.  In Chapter 2, he showed that he saw nothing wrong about making arrangements to see his mistress right under her husband's nose, and in Chapter 4, Nick revealed that immediately after his South Seas honeymoon with Daisy, Tom was involved in a scandal with "one of the chambermaids in the Santa Barbara Hotel".