Should I marry a man who always threatens but has never hit me?

From a female LIB reader

I've been dating this guy for almost two years now and although he has never hit me, he's always threatening violence. He would tell me things like 'If you don't shut your mouth, I'm going to smack you. Why would you behave like that? You deserve to be punched. One of these days I will give you a dirty slap. I don't take nonsense, I will beat you. You are pushing me, one of these days you will get it." He has been saying things like this for almost two years but has never laid a finger on me. Now he wants to marry me. I will never tolerate violence on my person and because of his words I'm hesitant to accept his proposal. When I told him what my reservations were, he said he's never hit a woman and doesn't plan to. So why does he say it all the time? My friend told me men change when they become husbands. Would he act out his threats when I marry him?