Does that mean it's too confusing to consider your S.O. your best friend? Of course not. "For some people, their partner really is their number one person, and I don't see anything wrong with that," Zimmerman says. It's important, though, that your partner is both a best friend and a lover. "If 'best friend' is just one of the aspects of the relationship that's wonderful, because you sure wouldn't want to have a relationship with somebody who wasn't your friend, right?" she says. And if you think about it, it makes total sense that people in a relationship would consider themselves best friends. If you've been in a relationship with the same person for a long time, then you're certainly spending more time with them than you are with your non-romantic BFF. So of course you want to like them just as much (this is not primary school, and you are allowed to have multiple best friends ).