In Season 7, Episode 2 titled Stormborn, Ser Jorah Mormont is informed that his greyscale is untreatable and that he has six months of sanity left. Archmaester Ebrose states that Ser Jorah will be exiled to live out his remaining days with the stone men. As a courtesy to Ser Jorah's knighthood, he will allow him one more day at the Citadel.
The next time we see Ser Jorah, he is writing the following letter to Khaleesi:
Khaleesi, I came to the Citadel in the last hope that the maesters could treat me, as you ordered. Even with all their arts, I am beyond any cure but the grave.
I have had a longer life than I deserved, and I only wish I could've lived to see the world you're going to build, standing by your side. I have loved you since the moment I met you.
Was Ser Jorah saying goodbye to Khaleesi because he was going to commit suicide or because he had failed in finding a cure and was going to live in exile?