why was grooming so normalized back then oh god

My friend just told me about how her mom and dad met and it literally started with "my mom was in first year high school and my dad was in college" like my jaw dropped when she said that then her dad apparently was possesive over her mother, he would fight other men just so that he could have her like even she my friend said that her dad was a predator it also doesn't help the fact that her dad is hella controlling and pretty traditional.