No, in my country saying “the couple solves their problems under the sheets” means that “that's their problem” and if you interfere “it's none of our business…”.
If they are crossing a line and inflicting harm, yes I would.
Many years ago I happened to pick up an injured person in the street and when I dropped him off at the emergency room of the health centre, the police detained me for more than two hours. Imagine if the person had died… After the event, it never occurred to me to do the same…