Congrats on your recent marriage.
Under the T/C of Marriott Rewards in the Conditions of Enrollment it states "only individuals are eligible Rewards Program Membership" and it goes further under the Elite Membership General where it states "Benefits of Elite Membership are reserved for members only.
Sorry to lay out the bad news, but unless those terms change it doesn't look like your wife will be able to reap the benefits, of course if you were to travel with her!
I know what the terms say but this is not how it happens.
I travel 200-250 nights a year in a Marriott. My wife is the card holder and I am the one who uses it. When I make the reservation, I change the name of the person staying in the hotel. When I arrive in a Marriott, I never have an issue with gaining points, getting upgrades, booking travel on the 800 number, etc.
Sometimes, the 800 number will give me grief but it is not a lot and I have never had a problem getting what I wanted.