If it comes to the point where you cannot care for your animals anymore, or at least your horse, you can consider an animal sanctuary. Have you ever heard of Best Friends? Check out the website: bestfriends.org. You'll be amazed at the work they do. I know what you mean about being heartbroken if you were separated though. But, this place is definitely the place you would want your animals to be if you could not care for them anymore. I'm so sorry you are going through all of this.
Rebecca