What is the "great tragedy" in your relationship?

I think the core disagreement in my marriage stems from the things that one of us does or believes in that the other doesn't.  I believe that problems must be talked about and addressed; my husband doesn't.  My husband believes it's OK to shut down communication with me (i.e., not talking or texting for weeks at a time); I don't think this is OK.

Do you have a core problem or difference?  What is it?