Staying in Austria with partner?

Long story short, I live in Brazil and have an Austrian bf. I (obviously) hate it here so we were thinking I could stay with him, but how could I legally stay? If I understood correctly I can stay 90d without a visa or anything and after that, what I'd need either a job or to get married? Is there another way? I'm sorry if it's a stupid question. We looked over the website but didn't really understand anything too extremely well.