SM, since you are insisting that you can cherry-pick which of the definitions listed you will use, lets do the same.
Marriage: ": an act of marrying or the rite by which the married status is effected; especially : the wedding ceremony and attendant festivities or formalities"
Gay: "happily excited"
There, now we have used definitions from Mirriam-Webster dictionary for both "marriage" and "gay".
Now there is no mention of same sex or or sodomy.  In fact, no mention of gender at all.   So now gays can marry and it won't be any change at all.
The above definitions fit my wedding and, mostly likely, fit your wedding as well.