Why does Mr. Rochester order Jane and Mr. Mason to not talk to one another?

I think that Mr. Rochester orders them not to talk because Mr. Mason might know something about Rochester that he doesn't want Jane to learn about or have anybody in general learn about. I think it has something to do about his life in the West Indies or something to do with is ex-wife. From the way it was described I feel that Mr. Rochester has some dark secrets that he wants to keep locked away forever.