“Marriage involves a unique commitment between two people,
traditionally Biblically a man and a woman, to love and support each other for the rest of their lives,”
Fixed it.
The "who love and support each other for the rest of their lives" bit is a little deceptive. You can have mutual love and support in a long-term friendship. What characterizes the meaning of a
sexual union, specifically, and the relationship predicated upon that sexual union, is the begetting and bearing and raising of children.
They have cut the expectation of natural fertility clear out of the definition of marriage.
Now it's formally just for the satisfaction of adults.