Many mothers' friendships develop through children — NCT classes, school gate, baby groups. These friendships often dissolve as children grow up and life pathways diverge. Maintaining one friendship outside the mother circle preserves identity beyond motherhood.
What this looks like
Old friend from before kids. Work colleague. Hobby-based friendship. Anyone who knows you as person rather than as your child's mother. Worth deliberate investment as life gets busier.
Most mothers without such friendships find empty-nest years harder. The friend who knew you before children helps you remember who you are when they're gone.