I gave up my gf for the guitar too. She couldn't take the amount of time I spent playing... I mean, yeah, I'll go out with her, be back home @ 11pm? Then I'll play till 2am. Then rest, wake up go work. Repeat.
Then well, it came down to passion or love? Dreams or well... a more stable future?
I figured... I'm young, 22, I still have so many things I want to experience. I want to play guitar, I want to do music, I just wanted so many things that if I did not do it, I would be upset. Really upset.
You see a lot of 'I's there, yeah, it was a rather selfish thought. How to rationalise? You can't.
In the end, she realised that I was not going to be happy. She decided to call it quits.
Tis a sad thing, but truth be told, if you are < 30, I don't see an issue choosing the guitar over a girl. Please understand I am NOT demeaning ladies, or relationships I'm simply saying that there's more to life now, when you are young to do other things. Relationships can wait.
But thats my opinion.