Yes, I haven't read it yet, but a 2013 memoir by a woman who knew him discusses Nee's apparently well-known adultery & frequenting prostitutes. The book is Lily M. Hsu M.D, "My Unforgettable Memories: Watchman Nee and Shanghai Local Church."

I think the thesis I might have in mind already is that charismatic people are typically sexual people. The Christian world likes open, effusive, sexual teachers but requires them to conceal their sex lives…setting up disclosures later when the teacher is out of fashion.