that will be a tough one

I remember a film that begins with a private detective trailing a cheating wife and her lover.
He takes pictures of them and then the wife’s husband enters their hotel room and begins to assault them.
Also the private detective is divorced and at one point confronts her ex wife’s girlfriend in a bar.

That’s all I remember but that’s a film I watched when I was about 6 or 7 years old around 1991-1992 or 1993.
Anyone has an idea ? I believe the detective had a mustache but no sure and it was an american movie.

Not a perfect match, maybe
“Under Suspicion” (1991)?

That’s not the one. But I am watching it right now. Quite enjoyable. Thanks !