He says the vampires need him, want him, want to consume him utterly, and he needs that, wants that. He says Buffy never needs him that way, that much.
In the end, he ships out - later he meets another adventure buff, female variety, and marries her - another ep - and Buffy is left wondering and wanting.
And I am, too. Is "need" necessary for love? I don't think it should be. The bigger question - why would I use Buffy as a springboard for questions about love?