I agree with the outdoors idea. If you can go to a state/national park or anything that is close to that and take a walk that is always nice. Beautiful scenery, quite time alone with just you two, maybe a little pick-nick, sounds good to me.

I also like the hotel idea if you live in a more urban area. The problem I can see with that is if you are limited on funds a nice hotel can cost quite a bit. However, if you can swing it I think it would also provide for a nice little get away for you two.

It might help if you would list some of the things that are available in your area and possibly some of your likes for things to do.