I met her about a year before she passed and she was a lovely human who was very open and honest about her struggles with substance and sex addiction. I’d strongly recommend her book, not only some great Star Trek stories but also great stories about the struggles and ultimate victory over her vices.
Not OP, but op will likely say her autobiography as the source.
She does not directly name the person, but does allude heavily to it and furthermore caps it by saying a week after the event that Roddenberry had cut her role from the show.
I'm not particularly interested in this subject - too many years have passed and nothing can ever come of it - but just thought I'd mention what I had found after reading this on some forum what feels about 10 years ago.