Marriage is not the same in every place or time

"The sacred rite of marriage is a covenant between a man and a woman - always has, and always will be. "

Nonsense. Marriage has been many different things throughout history. Polygamy haas been practiced in many societies at many different times (heck, it's all over the BIBLE!). Women have been considered property in much of recorded history, and marriages have been arranged in order to create alliances between wealthy, land-owning families or even countries. The idea that marriage has been a sacred, unchanging institution is ridiculous. It has changed according to the needs of a given society or culture.

If marriage is only intended for procreation, then perhaps we should require anyone who is considering marriage to be tested for fertility. Anyone that can't have children can't be married. That's the logical outcome of your viewpoint. People get married for lots of reasons, with procreation being just one of them.