As far as Majel not caring, oh no, to the contrary, she cared too much. She cared so much she let him get away with it. I have never seen a woman so in love with a man as she was with Roddenberry. It must have been very painful for her to hear the stories of his relationships. She was an outstanding woman who put up with far more bullpoop than she needed to.
At the risk of sounding insensitive, let's remember Majel Barrett was once the other woman as Gene Roddenberry was married to someone else (Eileen Rexroat) with two daughters. She was also aware of his having multiple affairs at the time (Nichelle Nichols, etc ...). He was a swinger and always on the prowl. She knew the deal and some would say her pain was karma - that she was experiencing the pain and suffering she helped inflict upon others.
It also begs the question, what kind of person was Gene Roddenberry really? What was the quality of his character? Not the facade or manicured public persona, but the real, under-it-all human-being?
As much as I love "Star Trek," I have just heard and read too many stories from too many different close sources to realisticly feel Gene Roddenberry was a person that I would want to know or associate with.