I'm going to leave my significant other alone at my house after an argument.
Are you doing this because you want to hurt her?
I feel like I don't need her dumb ass in my life.
After a heated argument, it is normal to want to be alone for a time in order to cool off. However, you shouldn't think of your significant other as a dumb ass as it is very hurtful and can lead you to hold her in contempt. You should work on better conflict resolution strategies so you do not end up hating your significant other and sabotaging your relationship.
Fuck it. Who cares about our relationship.
I get it you're still angry at her but i suggest you to deal with the situation like an adult.  You take some time off and then talk to your SO. It's better if you don't call them names.