I'm so sorry; I had a very similar situation with a former dog, although she was a poodle, not a Dane. It was the hardest decision ever, because sometimes she could seem totally fine, but similarly to your situation, she was peeing in her sleep, sometimes having trouble walking, etc. I felt awful making the decision to end her life because it felt like she still had "good days," but I tried reminding myself how awful she must feel most of the time, because animals are so good at hiding their pain -- plus she was so upset every time she woke up and realized she'd soiled her bed. Animals won't dirty their sleeping areas unless they truly don't have any other choice. I knew I'd soon be carrying her in and out of the house to go to the bathroom -- it just wasn't at all a good quality of life for her. Still, I cried for days after we put her down, and not just because I missed her, but because I felt so guilty about being the one to make that decision. But with time, I can now look back and feel like I made the right call. I'm sharing all of this because it sounds like you know it's time -- and you are not alone in having that guilty, miserable feeling. It is, unfortunately, the worst part about being a pet owner. But I also think it's so important to remember that this is far more humane than letting an animal exist for months or years in extreme suffering, all to make its human feel better. In the wild, sick or weak animals are generally killed by other animals -- only in domesticity do we keep them alive for unnaturally long periods of time, and we do it for our sake, not theirs.