I know practically nothing about Jada, and how her intimate relationship with Will Smith is, but this is how I analyse the situation at the Oscars just trying to judge the situation by itself:
From what I have seen, most people seem to be thinking that Chris Rock's attitude was the praiseworthy one, while Will Smith was wrong in hitting him.
But I disagree with that;
It wouldn't feel right if Will Smith had just laughed about Chris Rock's joke about Smith's wife's baldness, that was caused by her alopecia. Especially considering how he certainly knows how much his wife has felt bad about her illness, it's just understandable that he, as her husband, wanted to do something to defend her in that situation.
Meanwhile, people are praising Chris Rock for being "so professional", instead of seeing how pathetic he looked there playing dumb and trying to treat is as a joke from beginning to end even though he knew how serious Will Smith was.
It doesn't matter what's your profession or how important the event was; None of those things can be placed over direct human relations; Even leaving aside whether or not it was right for him to make the joke, the natural would have been for him to at least get serious after getting hit, and preferably to try hitting Will Smith even harder.
Chris Rock's attitude was clearly one of someone whose mind is so absorbed in his title of "comedian" that he ended up losing the normal sense of reality, which explains why he thought it would be okay to make a joke about a woman's baldness due to an illness, and even getting slapped in the face wasn't enough for him to wake up to reality and act as the real individual that he is instead of keeping playing the role of comedian.
The only problems I see in Will Smith's attitude are that first he failed by laughing at the joke, and also that he ended up apologizing, even though there was no reason for him to do that; He could have just explained that he did what he did to defend his wife, and that should be enough.
And I also believe that his wife lacked the common sense of wearing a hat to make her baldness less noticeable, if she really didn't want people to talk about it. But that's her own problem; This doesn't change the fact that Will Smith's attitude as a husband was correct trying to defend her in that situation.