Forget romantic, go were the food is great. Everytime I go home to visit I go straight to Padrino's (near Potomac Mills). I'll be back home on July 2 for the holiday. If you like bad ass pizza, cheesesteaks, etc, that's the spot.
Take him to the Dandi (sp) in Oldtown Alexandria. You probably need a reservation. But yeah if he digs those kind of things - good, if not there's always Five Guys for great burgers!
We ended up going to a chinese buffet. Very unromantic, but you can't really be romantic when family members on both sides join you. but it was great food and great company. i would have loved cheesecake factory. good suggestion Lisa. we couldn't wait that long though.. tee hee