Why don't my parents divorce?

I live in a house with my older brother who’s 21 and I’m 18. My parents literally fight everyday, at least a few times a day. My dad always tells me how much he dispises my mother and my mom complains to my about my dad on a daily basis. My dad talks about divorce several times a week. We are all VERY unhappy in this house. I don’t understand why don’t they get a divorce. It would solve everything, I know it would. We would all go our seperate ways and that’s what we need; Or at least that’s what I need