A.M.
Hotel Zaza,The Crescent,and the Melrose are my favorites. There is also the W Hotel near the AA center which has the restaurant Kraft,and the Ghostbar up on top. There are tons others within walking distance such as N9NE.
Hotel Zaza has the Dragonfly restaurant,and Crescent has Nobu.
Zaza,W,and Crescent are all going to be pretty expensive for a room, but the Melrose and the Wyndham Anatole Hotel(which has the Nana Grill) are going to be more moderatley priced. All of them great hotels and restaurants so you cant go wrong!
Have you considered a romantic little bed and breakfast? I have been to Elm Creek Manor and it was SPECTACULAR. They cook you diiner,decorate your room with rose petals,and there is the Winstar Casino only 10 minutes away. It is about a 45 min-1 hr drive out of Dallas.
http://www.elmcreekmanor.com/?gclid=COfZmLy81Y0CFRNkYwodo...
If you would rather stay in Dallas,there is the Corinthian which is located on Swiss Ave. http://www.corinthianbandb.com/
Another is Maple Manor which is in uptown dallas. You can walk to the Old Warsaw restaurant or several others. http://www.dallas.com/maplemanor/
Bed and Breakfasts have a more "intimate" and romantic feel. Hotels seem a little,cliche.
What a wonderful wife you are to do something so special for your hubby's bday. :)