Love is Always Different Always Changing

I heard the question many times but tonight I can't seem
to get it out of my head.
How do you really define Love?
The Love you feel is different with every person.
I love my parents, But it is not the same type of
love I feel for my spouse.
And very different from the love I feel for my son.

I also look at other families.
I have friends that have several kids.
They all tend to have a favorite whether they
want to admit that or not.
They tend to feel more love for one then the others.
They love them all, but all in different ways.
How can you define something that is always changing.
I know there is no correct answer to my question.
What makes us love people so differently.
Sometimes it is a quiet safe love.
Sometimes it is an all consuming love.
All love is a gift and to be treasured not measured I guess.