As for Proposition 8, leave religion, politics, tolerance and emotions out of it.
It's simple. Just look up the definition of "marriage" in any dictionary, and you will find that it clearly states that it is "the formal union of a man and a woman, typically recognized by law, by which they become husband and wife." That is marriage.
Unfortunately, Prop. 8's intention was to change the definition of marriage to fit a purpose for which it was not designed.