Question on tax exemptions?

My husband was in Iraq (oct 05-oct 06) and I did the taxes while he was deployed. Is that true that if your married and (even if you don't have kids), you can get tax exemptions for your spouse? (I don't work) I don't think we've ever had any tax exemptions ($3,300 I've heard) ever since we got married? If that's true, could we get money back for previous tax exemptions of the last 2 years? Let me know!