When i'm standing on the roof of a building I have an very powerful urge to
jump. I have to move away from the edge for fear I will act on this feeling.
I'm not suicidal and feel perfectly fine otherwise. I'm 38 years old and
cannot remember when these feelings started. Please help.

maybe it's just that you're craving freedom.. [:))]
or wishing to experience the thrill of jumping!! remind yourself that riding an amusement park ride will have the same effect as jumping off a building tho (do you know the mega drop ride? it's fun [:))]) oh man i wanna go to disney world... :D:D (sorry this is off topic...)

I know what you mean by this. Though it very well may be a subconscious desire to commit suicide, I believe it may be also a mixture of an impulsive personality combined with boredom. Whatever you do, ignore these impulses! I definitely think it's something to talk to a real doctor about, for the very obvious reason that you're in danger because of it.