One thing that my husband and I try to do is go on regular dates. They are not always expensive, they are not always romantic, but we try to set aside time to spend together one on one. Sometimes when we let the busy-ness of life keep us from getting that intimate time together we can start to feel the strain on our relationship because of it. It is definitely worth the time and money to help stay connected and show one another that we value our relationship and desire to deepen and strengthen it.
For more info check out the article I found: "How to Date your Spouse" on Crosswalk.com. There are also some good resources related to the movie FireProof.
I did a yahoo search for Cheap Date Ideas and got tons of good sites ( a few not so great) here are a few that I liked:
Cheap Date Ideas for Parents
Cheap Romantic Dates