I was once yelled at by an interviewer who hadn't yet made me an offer when I told her that I had accepted another offer (a way better one). I hadn't meant to deceive her into thinking she had more time to decide, and she was wrong to yell at me, but it made me realize that it's better to be crystal clear about your timeline to avoid burned bridges. I agree with the commenters who say to ask Company X for a firm deadline and let Company Y know about it.
Girlfriend needs to wake the hell up.
My parents are the same way. My dad taught me to collect and roll all my change when I was about 3 years old, and it's one of my favorite annual activities. Never use Coinstar--what a rip-off! Through my mom's influence, though, I willingly spend $300 on nice work pumps. I am entering her career, so she taught me that it's important to look the part!