I think you need to do what's best for her. We have been in a situation with one of our Dachshunds, her back went out for the third time and this was the worst time. I didn't want to put her down, I was being selfish because I wanted her to stay around and not go anywhere. I didn't even think about what type of life she would have, I just didn't want to loose her. My mom and I finally talked it over, keeping her around would do nothing for her. She would suffer more and putting her down was the best thing for her. I'm not glad we had to put her down, I'm just glad she is not in pain anymore. I miss her all the time but I know it was best for her. It's hard loosing a pet since they become such parts of our lives, but if it's time then it's time. I think about all the fun times we had with Roxy and I'm happy for those times we got to spend with her. We need to take care of our animals and do what needs to be done. Just my two cents!
It's hard now but I swear things will get better. Whatever decision you and your family make will be the right one. ♥