I resigned from my company and my boss took it very personally.
I am a software dev and found myself in a position of a sole owner and maintainer of a rather complicated project. I gave a proper resignation advance notice of more than a month, which is longer than the contractual or the legal mandatory period of advance notice.
He stated that it was morally wrong not to raise flags and to make an appearance of an employee that is content with his position.
According to his position, although I am not at fault legally or contractually, I did put my company and himself personally in a difficult position, and he maintains that I have should avoided it by being upfront about my plans to find a new place of employment.
I am aware that it will be difficult/expensive to replace me in a short time, but I don't see it my responsibility to mitigate this risk for the company at the expense of me disclosing my plans and as a consequence putting pressure on myself to leave in defined a period of time, or limiting my options.
Does he have a case? What is the norm in such circumstances?
How can I behave to diffuse the situation on one hand, and assert my position on the other hand?
Currently I am under impression that my boss is very tense and is acting out of emotion rather then reason. I don't want to alienate him or make the conflict protracted by hurting his ego, but I also don't want to take the fault about something that I don't feel I am at fault with.
EDIT:
I'd like to save the good relation with my boss, though I'm in doubt it is feasible now...