Should i get another dog?

i have a three year old maltese but he doesn't react well to other dogs. anyways, i really want another puppy. and i'm not sure if its such a good idea. im scared it will be a lot of stress if they don't get along, but if it makes it better by letting my dog have a friend at home when we're out that would be AMAZING. our family treats him like us and we love him to death. and we want him to have a buddy. but what if we buy one and its a huge mistake?