Hello. My Fiancé Has PKD (diagnosed 6 Years Ago) And

Hello. My fiancé has PKD (diagnosed 6 years ago) and is the final stages of securing a kidney transplant from his younger brother. He gets moody and sometimes gets depressed that it's not happening fast enough. He now says that he will have a whole new life after his transplant and is looking forward to "new beginnings" that don't necessarily include me. I know he's very stressed and has been disappointed in the past that other live donors have not worked out, so he's had to go back & start the process again four times. Is this causing his wanting to end our relationship and "wanting to start his new life"? I have been very supportive and have even offered him one of my kidney's. Do you think this May be a factor in his new thinking? Please help as I am completely confused. Thank you. Karen