If two men or two women marry- none of that changes.
But it does change. There are no distinct mother of father figures in that so called "family" Girls/boys would not have the affinity to their opposite sex
I will review slower this time for you:
Family #1- Mom and Dad with 2 children- not married.
Family #2- Mom and Dad with 2 children- married
Family #3- Mom with 2 children- not married.
Family #4- Mom with 2 children- married but husband has abandoned family
Two women marrying doesn't change any of those families.
Family #5- Mom and Mommy with 2 children- not married.
Family #6- Mom and Mommy with 2 children- married.
When the couple in Family #5 marry, none of the above changes- other than their children now have married parents.