Troubles with our dachshund?

Our two year old neutered male dachshund has become very aggressive over the past year. He is very territorial and is snappy with my other dog (a golden retriever). Oscar has nipped my kids and recently did the same with a neighborhood child that came running into our yard. I have decided to find him another home because he is just not working out for our family but I am feeling terrible about this decision. As far as I'm concerned a dog is not something you take on lightly. Oscar is a member of our family and I feel as though I'm abandoning him instead of dealing with his behaviors. I've considered having a dog trainer assist me with overcoming this problem but I'm worried that I could never fully trust him. The home I've found for him is wonderful. They have acreage and other dogs including his brother and sister. He would belong to an older, retired couple that has tons of experience with dogs. It seems like the right thing to do yet I am sooo heartbroken. Please give me your opinions. Is this the right thing to do?