Every Wednesday, Joan and Syl leave work early, go to his place, for an afternoon delight, then arrive at the meeting.
They never enter together. They always arrive a few minutes apart. They might not even sit together.
At the end of the meeting, they leave and go to dinner.
Just in case Seth is getting suspicious about his wife’s Wednesday meetings, he will be allowed to ‘overhear’ her telling a friend;
“No, I always work late on Wednesday then go to my meeting, and have a snack after…”
This explains her movements.
For a woman, having an affair means not being caught having an affair.