I support the equality of all citizens under the law. I do not support the equality of all practices under the law. We tried that in regards to race and gender allowing both the practice of inclusion and exclusion, it didn't work. We had to choose and we wisely chose racial and gender inclusion.
Gays want us to carve out an "exception" to gender inclusion for their marriages. For example in 17 states Gay men can now legally exclude women as a class from their marriages. This is a radical redefinition of marriage that points it in the opposite direction. Prior to 2003 every state mandated that marriage be gender inclusive.