I have received my MSc. degree at software engineering 5 months ago after a 3-year period of study and research. At the time of graduation, my supervisor asked me whether I would like to continue as his PhD student, I said I'll be happy to continue with doctoral degree under his supervision, but I didn't tell him anything about my curiosity about working in the industry.
When I got my master's degree, I also started working remotely in a bank as a software developer. At first, this was just for exploring the industry since I did not have any previous experience. However, I really liked the environment and the challenges that I have been dealing at my job and I got promotion last week which resulted in a huge increase in my salary which is great since there is an ongoing economic struggles in my country and it helps me a lot. My supervisor knows me as a part-time engineer in the company but in fact I am working in a full-time position.
While I was working on my master's thesis, we also wrote a paper, which is related to my thesis (in some parts), in collaboration with my supervisor and another student who was a fresh Master's student then. We started this work 2 years ago and we got the initial outcome as the programming, writing/revising the paper part completed 1.5 years ago. Until then we applied for publishing our paper at 2 different international journals but rejected from both. After each rejection we spent a lot of time for both revising the paper and modifying/enhancing the implementation(code). 3 months ago, we applied for a 3rd journal and this time they suggested us a major revision. In last 3 months, I cannot work intensely on the paper and code revision since it requires indeed a major revision. My supervisor is not satisfied with my recent work and it causes stress on me although I will not continue with a doctoral degree. There is a huge amount of unfinished work of code/paper modification and the other student should be responsible of this burdening job. And I also told my supervisor that I want to continue with doctoral degree since I was not sure at the time of graduation. I feel guilty due to this to my supervisor but more to the other student.
So my question is: How can I kindly tell my supervisor that I would like to continue as a software developer in the industry not as a PhD student although we have an unfinished work? I will be happy for any of your suggestions.