Seems (to me anyway) that you should ready yourself for sleeping on the couch once you move in with your gf.

I agree with Chippermonkey, you should re-evaluate the longterm potential as your gf is already choosing to share her bed with her dog instead of you. I'm sorry but I just don't see ANYBODY being ok with that for any length of time.

Don't get me wrong, I'm not trying to be cold.I have BP as well, and have heard how helpful service dogs can be. But REALLY now!
What is going to happen during the night, while shes asleep, that she may need her dog for?

Sooo either you accept you'll be sleeping in seperate rooms until the dog dies, or think twice about moving in with her for now.

Maybe if she sees your hesitation she will realize how unreasonable she is being and consider having the dog sleep elsewhere.

Afterall, like you've stated, she sleeps fine without the dog when she's away from home. So this isn't a matter of "cannot" but rather "will not"...