As many have already said, the key is balance.
I have been married successfully for 27 years and found that balance is the key to everything involved in marriage. If you wanted to describe how to have a successful marriage in one word, that would be it, BALANCE.
My wife is very supportive of me running, but does not run herself. I try to make the runs as unobtrusive as possible. I also schedule into my running plan time devoted to my wife. Nothing short of emergencies interferes with these times. She is more important to me than anything else in life and I make sure she knows that. But then, I am a blessed man. I have the best wife in the world.