Generally it's both... People might hate my answer but here it goes lol. My boyfriend gets a little bothered sometimes when I look especially dolled up, but I like to look good. For myself, it's a confidence boost. For my boyfriend, so he has someone to really show off and feel good about being seen with (not saying looks are or should be the focal point of a relationship, just stating it's more of a bonus for him). In a way it is for other men too, my guy gets an ego boost if he catches men checking me out. And I guess we can for competitive reasons too... you don't want another girl to look better than you to your guy or the person you're interested in... if they inevitably do then you want to at least come close.