OT- how do I fix it so I don't have to connect my Facebook to log in anymore?

I regret fixing it that way when I first signed up for this site, but I had no idea I'd be unable to change it. My phone is a bit outdated and not a touch screen, so logging in to sites on it is sometimes hard. I can't connect with FB on it so I simply can't log in on my phone, just computer. is there a way to fix this? Thanks.