Very few people realize how tragic post s5 jmart would actually be. Provided they really end up Somewhere Else, Jon possibly would’ve been freed from the Eye. He would be without the thing that made him the person he knew himself as. Having to find himself again. Not even knowing if he has the strength to do so.
Imagine how Martin would’ve reacted to that. At first he would be happy with it - after all, it’s the Beholding-less version of Jon that he grew attached to. But after some time he would realize how little of that Jon is actually left. How much of Jon’s very being was intertwined with the Eye, and is now lost forever. A part of your beloved is dead and you will never get it back, not as you had known him.
Still, that helpless Jon would be Martin’s favourite Jon. He could finally dedicate his time to taking care of him, just like he always wanted. His perfect little scenario of them living a domestic life could finally be realized.
The thing is, Jon doesn’t like being weak and helpless. He had always taken care of himself, and he can do it just fine. It’s mental support that he needs. Those “monsters” may be gone, but the Fears, their statements, the suffering - they all linger in his mind still.
But Martin has already left those events behind. He doesn’t want to go back to them, because why would you want to relive those awful moments? You’re fine now! Here, I’ll make you some tea. It will make you feel better. Just try to sit down and relax.