My husband and I had a dog for dog for 10 years that we were incredibly attached to, that became increasingly aggressive over his final couple of years (including a few biting incidents). We worked on training, we bought a house with a fenced in yard, and we worked it out so our lives revolved around our dog's issues. Having friends over was stressful, traveling was a huge issue, etc.- it sucked a lot, but we were so used to it that it seemed normal (and in our case, the dog was fine for a while and only got bad as he got older). We ended up having the dog euthanized when our oldest child was about 6 months old and just starting to move around, and the dog had growled at the baby a couple of times... for all that we tried our best to make sure the dog was never in a position to hurt the baby, we couldn't imagine that we'd never- over the course of the kid's entire childhood- slip up at least once. It sucked. That dog, for all its issues, was also part of our family- he was a jackass to other people (and dogs) sometimes, but 99% of the time with us, he was awesome. But just knowing that he couldn't be trusted- and worrying about the physical, emotional, legal, and financial repercussions that could result- was insanely stressful. We thought about trying to rehome him, but we figured that with all the great dogs out there that also need homes, we wouldn't wish his issues on another household. About six months later, we adopted an older dog who had been fostered in a home with kids and other dogs and done well, and three years later I still marvel at how relaxing it can be to be a dog owner. Having this dog is actually pleasant- I don't have to worry when friends or family (even toddlers) come over, he can interact with other family members' dogs, I don't have to freeze up when we cross paths with other people or dogs during a walk. It sucked putting our dog down, but I still think it was the right choice, and it allowed us to open up our home to another dog who needed one.