Earlier quoted context omitted.
Elon shouldn't be sleeping or hitting on his employees (see: exposing himself to a flight attendant). She's also on the board of one of his companies and held that position for less than a year before becoming pregnant with his children.
He only comes in contact with his executives. If out of them someone wants to be in a sexual relationship with him, that is their prerogative. A lot of companies have rules to clarify with HR when something like this happens.
Most HR departments don't approve of managers having sexual relationships (or children!) with their subordinates: it quickly becomes difficult to tell if preferential treatment is happening and presents possible legal problems.