What is love?

What is love? What do you think it is? Is it somebody who says nice things to you, someone who smiles at you, someone who makes you feel good about yourself? We grow up saying I love you to our parents, even when they have done bad things to you. Do we realy love them, in that case, or do we say it because we're tought to say it?
What is love? What makes us say ''I love you'' to somebody? Why, all of a sudden when in a relationship we say "I love you"? Why is it that we can love many people all at the same time? Can we truely "love" 2 people at the same time? I mean 2 different people in a romantic relationship. Or is it that we care for the 2 different people for different reasons? And if those 2 people if put together would be the "1" true love? What if you love someone but can't have them? How do you move on? Isn't love forever, or is it for that moment? That moment could be for a day or 50 years. It depends on both parties. What is love?