What are you expecting their employers to do.....fire them? If they are worth their salt, the employer "might" give them a slap on their wrists, but do you really think they will lose their jobs? All your W has to do is tell her boss that the two of you are S and she is going to file for a D. Maybe it is different where you live, but I haven't seen too many places where they cared what the employees did after hours. Now if you could prove they played around while on company time....that may get the boss's attention. But just b/c you tattled on them, doesn't mean the boss is going to give attention at all to it.
I know it's probably just my POV, but unless the LBH can offer something more than this, then why would the boss do what the H wanted.....and lose what might be two good workers? (The boss doesn't care that there has been conflict between your W and adult sons.) The only thing the boss is going to be interested in...is how does it effect business?
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!