Here are a few ideas...I don't know if they will apply to you, but these are things that I have done for date nights and also some of my girlfriends have done with their husbands, fiances, etc.
1. Play a sport together...(I know the weather is cold so this might be something to do when it warms up) Tennis, Volleyball (indoor or outdoor), whatever the sport you are both interested in.
2. Board Games (These work when it is just the two of you or also if you are ever getting together with other couples)
3. Bowling (I guess this could be considered with number one) however, dinner and bowling go quite nice together sometimes
4. Take a train from Grapevine to Fort Worth
5. Zoo (also good if kids are involved)
6. Workout together (whether at a gym or just outside, or around the house)--this might not be your idea of fun but it is always easier to workout with somebody--my husband comes to do yoga with me sometimes and then we go out for a yogurt or movie or whatever we decide to do that evening
7. Improv comedy show---somewhat like a movie but you are free to talk a little bit more---my favorite is Adlibs.com
8. Couples Massage
9. Paint or some other artistic thing together
10. Cooking classes for couples (there are some different options around Dallas and Fort Worth)
11. Wine Tastings or even a make your own wine (in Grapevine, TX)
12. Museums (art, science, etc. )
Ok, so I know these are kind of all over the place, and I didn't have many specifics, but just search the ones you are interested in because there is a lot on google or even the different city websites.