Marge met his wife and two other mothers at Toddlin' Town where she once took Bart when he was in preschool. They soon became friends and established a club called The Cool Moms. Their husband then had to meet every time their wives were together. They hated it and were glad when the club was disbanded.
In the present day the mothers met again and the club was restarted. It meant their husbands had to meet again. They were just quietly sitting somewhere and really wearied. Homer sometimes tried to break the silence, but the other husband just criticized him.
When the club was disbanded again, Marge mistakenly thought they were good friends and wanted to be together, so she didn't tell them anything.