This reminds me about that thing about " known knowns and known unknowns and unknown unknowns"
I reckon whatever it was about Jack that Lureen didn;t know was a known unknown to her, and one she didn;t delve into. She was clearly more irritated by the impact his absence would have on the business, and by the amount of driving he was going to do, than interested in the reasons for his going.
There are, I think, things about which you choose not to ask, things you choose to ignore, and that's what I think this whole area might have been to Lureen.
"Don't ask, don't tell"?