Is my boyfriends habit really an addiction?

My boyfriend and I've been dating for 2yrs. Lately we've been discussing his unwillingness to commit to marriage. He says I'm the one yet when we start discussing it he freaks out. I originally thought it was due to his overbearing mother and sister whom he constantly has to run off to take care of - even though his mother is married and his sister is a grown adult with two young children. But, I just found out through a conversation with him, that he watches when I am not around. I have always been distgusted by it and when I questioned him about it he said he didn't want to tell me because he knows how I feel about it. He said he gets lonely and sad on the nights I'm not with him and that he needs a "release". I'm a child and family development major and I know that the line between a habit and an addiction can be very fine, but I am now worried that the real reason he doesn't want to get married is that he is happy with being with me on sporadic weekends, and is happy with his all those other nights. I have read and researched this topic alot and I'm very concerned and am re-thinking my relationship with him. Are my fears blowing up or should I really be concerned?