Expressions

Thats the biggest oxymoron I ever heard. No love in this world is unconditional. Especially between a guy and a girl. For some reason, I feel its the nature itself like that. Look at any species in the nature, its always male that lowers its head in front of the female. Including the humans. I never seem to understand why only guys should bend down on knees and propose a girl, and why not the other way around? Why the girl expects the guy to make the first move? And furthermore, they seem not to be interested in any physical stuff though they need it. Why?
What is conditional love? One of my friends says that his girl friend always says, "you love me unconditionally, irrespective of what i do" but she would complain on everything he does. Now expecting unconditional love itself is on a condition kind. And more so if the person who says it doesnt follow what he/she says.
Unconditional love - what does that mean anyway? You just constantly love someone irrespective of what you face? Who loved whom like that? Would the person who loved be able to take it when the person whom he/she loved turns a back to them?
May be I should understand that there are hardly anything logical in love. It doesnt make sense for me, but may be thats the way it is. If so, isnt there a single girl who is equally confused as I am, and looking for a logic in love? Somewhere, someone is searching for the logic as I am looking for and someday we both should meet.