It all really depends on the theme or the "feel" of the dreams. If the dreams feel frightening or in any way unwelcome to you, it may be a bad thing or a possible malevolent being playing games. If the feeling or the sense of the dream is a good one or one you are comfortable with, then all bets are on your ex boyfriend saying hi now and then. And that can only be a good thing.

Also, try thinking about any feelings or sensations you are usually left with after the dreams occur...after waking. If you feel as if there are any misplaced feelings then you may be possibly empathing onto the being/boyfriends current feelings. If not, don't worry about it. Loads of people dream about loved ones that have passed away and it is quite normal for a beloved to contact someone they once loved in their life. They are probably trying to show you how much you meant to them, and how important you still are.