My girlfriend (28F) doesn’t want me (27M) to keep our current dog because she’s old and thinks she’ll cost more money than we need to spend. How can I respectfully tell her I’m not getting rid of the dog?

Me and my girlfriend have been dating for 6 years. I brought a dog into the relationship who was 5 years old at the time. The dog is currently 11.

I had conversation with my girlfriend about this and the possibility of another dog. The first thing she said was "No, dogs in general are expensive. Which reminds me, you should get rid of the brat we have right now because old dogs like her are so much more expensive."

After she said this, I told her that the dog was MY best friend and something I would NEVER get rid of because she means too much to me. I told her that the dog matters more than money. She got PISSED. She said that the dog should matter less than what she wants because we've been dating for 6 years.

I simply got up, and left the room to calm down. The dog has never been a problem. She hasn't had to do ANYTHING with her other than feed her at night when I'm at work. The dog hasn't ever been a problem in the time we've been dating. She's mostly lazy and the most she does is a daily walk that my girlfriend hasn't ever had to do. I've owned this dog for longer than we've been dating and this dog gave me the love that I wasn't able to get from anyone.

How can I tell my girlfriend that I'm not going to get rid of the dog? I don't want to cause more problems than needed, but I do care about my girlfriend and don't want to lose her because of something as stupid as this.

Edit; Thank you everyone for the advice. I didn't think there would be so many people helping with this. I have decided, when I have the time, to get rid of the girlfriend! I can't be with someone who, like many of you have said, who will not care for me when I'm old and sick with her, or who will divorce and leave me when our children turn out to be "too expensive". Me and pupper will on-line our best life without that weight on our shoulders!