Why does my husband not defend me?

Here's the story: My husband came to me and suggested rather strongly that we have a friend of his live with us for a short time. This friend had just been recently divorced and didn't have a home. (Let me add that his wife divorced him for physical, mental and emotional abuse). After a couple months of this, he successful got out of paying his share of rent with my husband. One morning, I came into the kitchen and discovered some expensive food that I bought specifically for my health needs gone. I shared with this fellow that I did not appreciate him eating not just some but all this food. If you had been a guest for a day or two, I would never have said anything, but you are now here for nearly 6 months. I cannot afford this. The friend started yelling crazily at me and even told me that he bought the food. Weird. I told this man you need to pack up and go now. All the while that this man is yelling at me, my husband is sitting quietly on the coach. When I told Paul he had to go, then my husband spoke up for the first time and said: "Paul's not going anywhere." This pattern of my husband not defending me continues in our marriage in different ways, but basically the same thing plays out. We have talked about this, and he excused himself as a dumb husband who didn't know better, but yet in different ways he's not there to defend me. This humiliates me when he does not defend me like he has done in this story. Why does my husband not defend me?