While I cannot see into all the corners this could go, I see one.
Humanity is made up of two sexes, genders, the male and female. The union of the two provide us with the children that continue our kind by procreating according to ancient customs across the many nations no matter the languages, customs, or borders separating us even from ancient times.
It is therefore my belief that the homosexual forcing of marriage of males with males, females with males is an unholy union even without taking religious values into consideration. Simply viewing what exists naturally, I will not accept their definition or the laws definition of this unholy union as being anything close to marriage. I will not let others impose on me this one thing. Others can do as they like, call me all kinds of names, etc. But, their calling this marriage is an abomination.
That they engage in whatever sexual activities they want to - is an entirely different question. People do as they want to and always have. Their actions do not affect me, but making their union into marriage does. And, that belief is unacceptable to be, and shall not be accepted.