It may be that you don't have to make one choice or another. Perhaps you can get a therapist who helps you sort through what is most important to you for the time you have left on earth. Then you focus on creating that life, and shift the focus of your life on your own joy and fulfillment. There will inevitably be shifts in your relationship as you let go of what he needs and caring for him, and focus on creating your own life. It may even mean that your living situation shifts, eventually - perhaps you live part time closer to your friends and family and part time with him. Perhaps the two of you move. This way, you are not deciding to divorce the person you love, but instead slowly creating a life that is full of love and joy and connection and the relationship with him naturally shifts as a result. Perhaps it ends in divorce, perhaps he decides to shift with you and the relationship becomes something new. But either way, I hope you don't give up on living your best life while you still have time...