from what I've heard about Lee, she was pretty "wild" (for lack of a better word)I think you might be giving her too much credit.
Onassis had such an emprise on both her and Maria, he would have demanded that and more.
Don’t forget he was her sister’s lover first. At the time he was incredibly wealthy and beyond common.
And she wanted to marry that toad in the first place. She sold herself to him to put it politely.
Jackie wanted to marry Onasis for his money and the privacy/protection it would bring but I don't see her cavorting in front of the staff. Onasis must have seen her as a big prize. would he have mistreated/embarrassed her prior to marrying her?