Part of a successful relationship is having compatible goals in life. There is no correct answer to how much work is too much. Some people want to never work and spend all day on the beach. Others think the beach is boring and would much rather be creating something. Most people are the middle.
If your girlfriend thinks you work too much, you probably either need to work less or get a new girlfriend.
One thing that is definitely not "quality time" is fighting over how much you are working. Everyone loses.
Your comment is totally reasonable and I'm certainly not suggesting dropping someone the first time compromise is required.
But I don't see why there needs to be so much emphasis on couples staying together. The OP doesn't say, and it is certainly possible that I am making incorrect assumptions, but it sounds like they are young and don't have children together. (no one over 30 would say "gf", right??)
So who cares? If they are meant to be, the work/life balance won't be a big issue. If they are incompatible, better to find out now, before they are older and DO have kids.
I want to add that the readers of this site probably put way more time into work (and work-related activities) than the typical person. If your significant other expects work to be 9-5, you should probably disappoint them sooner rather than later.
If your girlfriend thinks you work too much, you probably either need to work less or get a new girlfriend.
One thing that is definitely not "quality time" is fighting over how much you are working. Everyone loses.
Good luck!