Lust was obviously not happy with his lifestyle in Turkey, because turkey is a ****. If a man is not satisfied with his life, that shows in his job. And captain lust was always lackluster in his job. He is too young for it, his words were never trust-worthy and everything he said was up in the air. I understand it at some extent but he should have done this a long time ago. Moving from UK to a country like Turkey will move you to a much lesser lifestyle. Many people cannot handle that. There's a point in your psychology that you simply do not give a ****. As said, I can understand it. It's time for someone more energised to handle the community.
edit: you also have to realise that a sane person would never leave UK for turkey PERMANENTLY. The budget that was offered to Lust would never be able to sustain him in the UK. There is a difference between loving your job and not being able to survive. I doubt Lust wanted to stay to Turkey forever. He probably though that Bannerlord would have been released by now. It is not his fault that he left, its a matter of lifestyle enjoyment and survival. You need to be happy and also survive.