My "ex" contacted me after six months - Should I try for a friendship?

I was seeing this guy for a brief time. He is in the military and so he lives far away and so on. We broke up about a year and a half ago and I half since being seeing someone who I am quite serious with. (We have even discussed marriage) and I am very happy. Well my old flame called me the other day just to see how I was and so on. Should I just take this with a grain of salt? I don't know what his intentions are but It would be nice to keep in contact every so often. What do you guys think?