Passed out and the ex-girlfriend used my finger on my phone to unlock it.

What makes you think a ex-girlfriend wouldn't be paranoid enough to look over at an 8-digit passcode or pattern?

Passcodes are at least easier to rotate than fingerprints. You get 100,000,000 possibilities with 8 digits, compared to 10 possibilities with 10 digits.

Very good. Took me a second.

Personally, I don't date anyone I don't trust with my passwords, work excluded, of course. Works out pretty well for me.

How do you know if you can trust someone that way without dating them in the first place? Only date people you've been friends with for several years?

Yes, actually.

I'm curious about this - is there some formal unveiling of passwords as a relationship milestone? Or does it just come up naturally, like, "I need to log into your gmail account, what's your password?"

Well, whenever one of us gets a new phone, we put the other's fingerprints in, just as something we started doing out of convenience. After that, yeah, pretty much. We don't share all passwords, but we would if we needed to.