How can he TELL (no pun intended) if she hit him on purpose or by "accident"?

When questioned in the police station, Peter Strauss' character gets told by "The Last Boy Scout" (1991) movie villain's actor Noble Willingham - "If you don't get more definite with me, I won't be able to help you, either they were or they were not accidents", but thing is, as a non-legal or non-social expert in such matters (social construct related services may take a different point of view on it than him), someone who clearly loves and is devoted to his wife (despite a myriad of physical and even emotional abuse she has put him through in this movie, and towards the end also, police suspicions!) and is maybe perhaps UNSURE and has never given it any SERIOUS importance?

Plus, what if he, for instance, THINKS that what happened WAS an accident, but let's say legal experts determine it was NOT, and that she, in that instance, hit him on purpose? Plus, if someone loses control and hits someone, at home or otherwise, is it really an ACCIDENT? And also...

I think given what we see, I don't think any of those hits were accidental, and some were deliberately plotted and carried out. But even so, given his mental and otherwise state, lack of proper legal expertise, devotion to his wife and even so much as not giving such issues before anything resembling a proper thought...

How could he tell whether her hits towards him were "accidents" or not, so that he really DOES get more 'definite' and that police "friend" of his or so could really help him? Thanks.

P.S. Does she actually get arrested and imprisoned at the end of this movie? TV Tropes site says she does but SPOILERS, you don't see that in the movie. Was it heavily implied? Cut out? All I got from it all is that he finally DIVORCES her, but I don't see any police trial or her getting imprisoned. Also, yeah, even if she does get jailed, does he pay her visits? Does he ask her how she is? Does he confront her with - "Darling, have you at least LEARNED your lessons?" type of mantra? How many years does she even get, 2 or 3, released in 1995 or so? Even if she isn't imprisoned, does she learn her lesson in other ways? Would anyone even WANT to marry her after they DO learn about all she is done? (I don't think I WOULD for instance but that's me and its out of the question, lol, haha, despite the seriousness of the subject here.)