What is/was the hardest part of your best relationship?

Hey Reddit, I am 22 and I work a low paying job (not minimum, but still low) I live in Tempe, AZ (just east of Phoenix for those non locals) My Girlfriend Lives in Canoga Park in LA California 400 miles away.

I only make enough money to visit her 2 times a year (for mine and than her Bday) and will be making my second visit to her for my Birthday in November. I absolutly adore her to death, we are practicaly twins when it comes to ideals, and interests. And this distance is the hardest thing I have ever experienced. But any moment with her (even 2 weeks out of a year) is completely worth the complexity of the situation.

Reddit, what hardships have you experienced in a relationship? Were they worth it? Are you still with that person?

Edit: pic of us together for her Bday this last March http://imgur.com/1yu9Y