Huh... I've always done my introductions... "Welcome Mr and Mrs John and Jessika Snickerdoodle...."
In my area atleast the man is always introduced first as he is considered the head of household... I know that sounds sexist but, that is how it is... So, putting the grooms name first on a monogram would be the way I'd do it too unless requested otherwise.
Very true Rob, and you're correct in introducing the male first because in a proper formal introduction, the male is first then the female. However, when you're talking about a wedding, the literature (programs, invitations, etc) the bride is listed first. It's just one of those fun little quirks about formalities.