So, there are just so many things wrong about your understanding of how a dog’s mind works in your description that I barely know where to start. Dogs don’t purposefully try to get humans into trouble like a tattletale. They are not that evolved.
The points that you have made indicate to me that this dog is truly afraid of the boyfriend – some thing he did years ago convinced her that she should be worried about him, and that has snowballed to what you see today. It may have been something as innocent as he stepped on her toes by accident. Dogs read body language and facial expressions better than we humans – and something as small as a look at her could compound her fear.
This is a very frustrating situation for you, and for the BF – you are both probably giving off negative energy without knowing it! She is picking up on the human frustration and it will only get worse if you don’t get some professional help.
And NOTHING you can do will solve this problem. It is a matter between your BF and your dog. So, you need to find a behaviorist that will come to your home and work with you, the BF and the dog. The behaviorist will be able to observe the dog and how you both interact with her and help you all find solutions to correct the situation. It is going to be a matter of your BF building trust with the dog. And since we can’t be there to watch the interaction, this forum isn’t going to be of much help other than by pointing you to professional, in-the-home, aid.
So, find someone that does positive training that can come to your home, and that you and your BF like so you can help your girl have the life she deserves – comfortable in her own home.
RIP Dr. Yin.
Would this be the same as counter conditioning to thunderstorms? I want to start working with my MIL’s dog – she FREAKS when a storm comes.