I don't know about finding a partner. I was married when mine was discovered. I am still married to the same wonderful man and we are quite happy. He is my care giver and goes with me to all my appointments, spends countless hours when I am in the hospital for surgeries. He helps me decide what treatments to use to help with my syndrome. My adult daughter has also been wonderful about being a sounding board and providing me the help in making decisions.
Sadly I have heard that some couples do not make it through together once this disease is discovered. I cannot address why that is - all I can say is perhaps that person is just not strong enough to handle the situation.