My girlfriend and I know each other’s passwords, but not out of, like, a defining conversation in which we ceremonially gave them to each other as a ritualistic sign of trust.
It was more like, “I forgot to print my term paper out, can you go email it from my computer so I can print it out at school? My pass is blah blah blah.” And then she knew my password. I wouldn’t date some one who I couldn’t trust with something as small as my password.