Many people believe that the guy should say it first, because they take longer to "get there" emotionally than women, and should "set the pace" on it. That if a woman says it first, he likely doesn't feel it yet, or isn't sure, and he'll either lie and say it back to placate her, or it'll scare the ever-living s*** out of him, and it'll all fall apart. Or he'll think the girl is a needy crazypants.