During my PhD I had an awesome collaborator that taught me a lot in an area that my main advisor had no experience at all. I have a paper draft with him that's getting more than 3 years to get published. He is extremely perfectionist and always wanted to add one more little detail here and there. With that, I don't mean from a writing standpoint. He actually asks for new calculations and analysis which usually takes months to finish. I read papers in this area which presented much fewer results and details than my paper. It's frustrating because I'm applying for faculty positions and I need this paper to show as a record of a very important part of my research plan. I explained it to him, many times. I also like him very much and would like to have him as a collaborator. So, I don't want to make pressure in a bad way. In short, he doesn't need this paper, he doesn't need the collaboration. He is a very accomplished researcher. Also, he didn't have any formal responsibility for my graduate studies. But still, I need the paper. We are in different countries, so I cannot have a one-to-one conversation with him. My former advisor cannot do much as well. My question is simply: what should I do?
I talked with my collaborator and everything went pretty well. I submitted my paper this morning!!! Thanks for the feedback. I think just the act of writing here, in addition to the feedback I got help me a lot to leverage. (I also followed some Carnegie's rules)