See, this is what I meant to say. We are talking about Love and Expectations. Love and reasons is not the right way to put it.
Talking about unconditional love, I think it does exist. I love my cat, she doesn't love me back. She hates human touch and scratches me when I love her. She would come to me only when she wants food else she would again scratch me if I try to interact with her. But I still love her. I don't expect anything in return. That's unconditional.
Similarly, when I became a mom, the child was giving me nothing. Not even a smile. It was all on me to give - love, milk, care, changing diapers, making him asleep. What did I get in return? Nothing. But still I love him.