This is a non-Catholic wedding anyway, being Novus Ordo, as long as the OP doesn't participate religiously in the rite it's fine to attend (as long as the couple aren't former Catholics).
People always provide vegetarian options at receptions and things like this. Just ask for the veggie option.
What do you mean by "former Catholics"?
Those who are baptized Catholics but have left the Faith. In this case I was referring to the possibility that the couple used to be trads but have gone over to (or back to) the Novus Ordo.
Baptized Catholic are bound to get married before a Catholic priest in a Catholic ceremony. The marriages are invalid of baptized Catholic who get married in a non-Catholic ceremony, whether or not they've left the Faith.
EDIT: This is AlanF, I forgot to click the 'Do Not Post Anonymously' button.