You and your boss discussed how you job was going to change. He asked if you wanted to stay in the position and gave you some time to think about it. A month later you told him he should get someone else to fill your job and that you would look for another job. You agreed on a transition period of six weeks. You resigned your position.
Pretty simple.
Your argument is similar someone saying, "You requested a transfer to a different department, so that means the same as "I quit.""
There was no misunderstanding between my boss and I as to what was occurring. I didn't want to screw over the store and leave a gaping hole in the position while they sought a replacement, so I suggested they find a more suitable candidate for their needs.
While this occurred, I would try to find a lateral position within the company.
Regardless, thank you for your opinion.