Tar Heel is right on the money. You'll find several posts if you go back a few days in this form, on this very subject.
My opinion (I go every year during Gay Days on business), whether folks are gay, straight, or purple, the crowds at MK that Saturday are nuts. As far as things you "have to explain," you'll see a lot of red shirts, and there is some hand-holding, etc. I've never seen any overtly rude actions (which is more than I can say for some heterosexual couples I've seen in WDW). But you may find yourself having to explain to your kids why Splash Mountain isn't worth two hours in line.
Pat