The opposite of love, an intense emotion, would be not be a different intense emotion, such as hate. To love something, one must invest a lot of time and emotional energy in it. The same is true of hate. Hatred also takes up a large amount of time and requires a huge emotional investment.

Apathy really is the opposite of both love and hate. The lack of any sort of emotion or investment in a person or thing is the polar opposite of love and hate.

Of course, I don't like binary oppositions, so I probably don't really believe what I just said.

Eh ... I guess I believe it a little more than what's been said so far, at least.