Love
Grimmjow did not believe in it. It was that simple. He knew Ulquiorra felt the same way. It was impossible, stupid, and downright childish. How could love exist in a world as cruel as this one? How could a feeling as pure as love make anyone happy? It didn't happen, end of story.
So he couldn't explain what it was that gave him butterflies whenever Ulquiorra looked at him. That took his breath away when Ulquiorra kissed him. That made him dizzy when Ulquiorra fucked him. Made him an amazing sort of happy when Ulquiorra was near him. He figured maybe he was just allergic to the fourth, should get away from him.
But at the same time, he knew he couldn't survive without him.
That's not what love was though. Love couldn't be such sickening feelings as those. It just couldn't be.
Owari