Is love a requirement in a long term relationship?

Long term, yes. Or at least the belief that there is love. See, there are a lot of people who are in relationships that they stay in because of the fact there's kids, or some other excuse that keeps two unhappy people together. They might have been in love, but when you don't want to be together anymore, there's no love there.

And sometimes people think they are in love, but it's really lust. When they realize it, they split apart.

If I didn't love Cordelia, she and I would have been over long ago. Hell, we fight all the time over the stupidest shit. But I'm in this for the long haul, and I don't plan on to stop loving her anytime soon.