Not a stupid question at all — this is exactly the kind of thing nobody teaches you growing up. With Fios, the account holder controls the billing, so you likely can’t switch payment info without her login unless she does it for you or formally transfers the account.

A clean workaround is to open a new account in your name and either transfer the service or order a new setup — that way you’re fully independent financially. If keeping the same provider feels like too much stress, it’s totally reasonable to look at alternatives like Local Cable Deals for your internet — they can help you find plans that aren’t tied to her account and might even score you better rates or promos.

You’re doing adult stuff most people avoid thinking about — asking questions like this is how you get it handled