I'm so tired of having to deal with girls who think they're in love with every boy they date for more than a week (I'll give them credit that they've been together longer than that but it hasn't even been a year). I think that, sure you can know someone really well, I know my best friend better than I know myself, but if you're in a relationship with some one you should at least take enough time to know what type of toothpaste they use and when their birthday is before sleeping with them, and take some time to figure out,all the things you don't like about the person (they leave the toilet seat up, do they squeeze the toothpaste from the middle, leave their toenail clippings everywhere) before you decide to "get married".