Furthermore while yes, loving unions existed, Judiasim (which Christianity branched off from) set aside a specific kind of loving union and called in marriage.

While marriage does seem to be a construct (there's no sign of it in the earliest societies), it certainly wasn't the Israelites who invented it. The oldest references to it are in the Code of Hammurabi, an artefact of the Babylonian civilisation from about 1760BC -- before the Torah was written -- and those aren't references to its invention, they're references as though it was already a well-established concept. (Of course, that's in archaeologists' dates, not young-earthers' dates; I guess if you believe that when the earth was created it already had two married Jews on, then that gives them a certain primacy.)

Peter