She's leaving. Because of Willow, she's leaving. It doesn't matter that you still need her, that the three of you will fall apart without her to break up the tension, see you off to school and make sure Buffy at least tries to enjoy her life. It doesn't matter that you'll have no one to make you pancakes in the morning for breakfast . It doesn't matter that Willow need her, and that she's sinking deeper; deeper into the majicks without her. It doesn't matter that Buffy is more and more withdrawn without her cheerful, southing voice to comfort her when she cries.

It doesn't matter that now you'll never get a chance to tell her, that she won't live with you from now on, that she'll have to make appointments to hang out with her, that she won't be there to confide in or cry to after school.

She's leaving, and it doesn't matter that you need her.

She's leaving, and it doesn't matter that you love her.