I have a 10 month old long haired chihuahua who I consider my baby! My boyfriend thinks I'm the reason for her bad behavior because I baby her so much. We have been fighting constantly on how to discipline her. He has 2 labs and I strongly feel that my chihuahua needs to be disciplined completely different than his dogs. She is only 4 pounds! He will yell at her when she does something wrong and go to pick her up to put her outside and she'll either snap at him or pee everywhere. I believe because she is petrified of him. He says I need to take control and discipline her when shes on the couch and shouldnt' be, or when shes barking, or has an accident in the house. I pick her up and smack her butt or nose but apparently to him thats not good enough. I'm not a dog trainer and I dont even know where to begin with this. But its starting to affect our relationship and I need to find a solution.

Any advice?