Last year I did my first competition, and my girlfriend and I came extremely close to breaking up several times. I was in school, working part-time, and at the gym twice a day for a total of three hours. When I was home I was either studying or cooking meals for the next day. There was very little time that we had to just spend together. I didn't go out because one, I was too tired and two, I didn't want to be around all the smoking and drinking.
It was extremely rough, and I almost quit training a couple times because of our relationship, but finally things worked out. I would not advise anyone to compete unless they have all the time in the world to devote to it and don't have a significant other to be responsible for.