To answer your question, I see other relationships enhancing our marriage just as friendships do. Having people in your life that you care about and care about you will enhance your life and therefor your other relationships.
I also wanted to bring up the idea that maybe he is struggling because of how you ask the questions. Maybe not, but I know that a few weeks ago I was trying to understand somethings and when asking Karma he took it as me attacking him or blaming him when all I was trying to do was understand. It was the way I was asking.