Military spouse ptsd

I feel helpless. My husband is a marine veteran and suffers from ptsd. He has a terrible time talking about things and any time I get him to even start talking he stops and holds back. He refuses to see a therapist. He’s so emotionally held back I don’t know what to do. There’s nothing more in the world he wants than a child and every time I get my period I feel like I failed him. I don’t know what to do. Please help. Any words of encouragement would be helpful.