Why is it that every time I have a dream, it's never a wet dream?

I don't have dreams very often, but I don't get the pleasure of having nocturnal emissions anymore. Either I feel nothing or it's imminent that I'm going to but then I always lose it and wake up. Why can't I ever go all the way? I don't masturbate as much as the average guy. About once every 3-4 days so I don't think that's it.