I've never eaten at these places, I'm more of an Elgin Street Diner or DiRienzo's kind of guy when I'm in Ottawa. But found these on the Ottawa Plus website under Valentines Day, but I reckon it should work for your wife's birthday as well.
Stella Osteria
Stella Osteria :: Modern Italian Food, Rooted in Tradition
Merlot Rooftop Grill
Home Page: Merlot Rooftop Grill – Ottawa Restaurant
Il Piccolino
Il Piccolino Ristorante > Home
Le Panaché
Le Panaché - Restaurant
Here's the Ottawa Plus link as well, they have a few more places I haven't linked to.
Ottawa Plus - Valentine's Day Guide - Romantic Restaurants