There are plenty public "gay" behaviors that aren't "bedroom" behaviors.  Being known as a couple, or married, or seen in public holding hands or walking with your family, like any "straight" couple/family is not "bedroom-like".    Discussions about sex or gentiality of any sort should always be age-appropriate and young children shouldn't hear about it.  If its on TV parents should turn off TV.  Once a child hits puberty, they should "hear about it."  Tough if you don't like it.