Unfortunately, accidents like this happen all too often and it is not always unsupervised children that get bitten, nor is it always the dogs fault. My nephew was bitten in the face at 8 months of age by my brother's doberman. He had the dog for 6 years and she was great with his son. His wife was folding clothes in the living room and the baby was playing in the clothes in the basket. He fell onto the dog, who was sleeping on the floor at his wife's feet. The dog was startled, bit him and he had numerous stitches at the emergency room. No permanent, disfiguring scars, but he does have small scars on his face and neck. My brother killed the dog immediately. He never took the time to think through what had happened. The baby had slept with the dog and crawled all over her for months. She was a fantastic, loving, protective dog, who loved her family. She was simply startled awake and reacted. It happens and is one of the things that we have to accept as a possibility if we choose to live with dogs. Just take a little time to think through your decision and make sure you are not being too hasty in your choices. If you really cannot take the chance of it happening again, take the earlier advice and work on finding a good, loving home for him, either through a local rescue group or independently. Only you can decide what is right for you and your children, but, keep in mind while some rescue groups will place dogs who have bitten, some absolutely will not adopt them out. We have some breed rescues here that won't even take the dogs into their program. The circumstances do not matter, they are simply not willing to accept the liability if anything should happen down the road and they were aware of a previous incident. Good luck with your decision and my prayers are with you.
Kathy