How do you balance work and your significant other?

Lately I have been putting in a lot of hours at work. I am 8 months out of college and into the workforce and I am very ambitious when it comes to my career. My manager recently even mentioned a promotion in my near future which makes me want to ensure that I am doing my very best and working hard even more.

However, my girlfriend recently got extremely angry with me. I want to point out that I have not been ignoring her for my job. We see each other at least 4–5 nights a week(all day and night on weekends) when I am not traveling for my career. I travel about 50% of the time and sometimes less. Once every other week usually and many times once a month.

Anyway, the breaking point: We had free box seats to a sporting event. I told her I may not be able to go because of an assignment from my boss. Long story short, I was told multiple times that the assignment could wait until the morning. I told my girlfriend this and that we could go. So an hour and a half later as we are parking, I get a call from my manager. I was needed for the project and it was critical that this be completed.

It is pretty obvious that she was beyond pissed and I can understand why. I wasn’t happy either, but the career pays the bills. I am sure I am missing some details here, but I just want to know what I should do and how to handle the balance?

Also, she likes really nice things and I explained that I can’t afford to provide those awesome things without the job that she hates. This made her angrier. Help!