It's impolite to keep plans from your spouse.
Mark gets invited on a weekend trip with friends.
Mark wants to go this trip without his wife.
Mark asks his wife if it would be alright if he goes on a trip next month with friends.
Mark goes on a weekend trip without telling his wife.
Mark's wife will be able to prepare for him not being there that weekend.
Mark's wife will be upset because she had no idea he was going away.