I think his wife should just clean up after the houseguests and watch their kids since she's the one who invites them over all the time. She should also grow a spine and tell her family to have some respect for her home and her hospitality.
Live as if you were to die tomorrow. Learn as if you were to live forever. - Mohandas Gandhi
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh
Thanks, I get what the problem is. His wife isn't listening to him.
So most other people's solution was suck it up or divorce. I simply suggested that he do neither. If she's going to continue to pass over his point of view on the subject then he can just play passive aggressive instead. So far this is the only issue the OP brought up where his wife isn't respecting his position or feelings on a particular issue. If this is the only instance where she acts this way, he has to pick his battles. If this is a continuing pattern throughout the relationship there is a much bigger issue, but that's not the way he's laid it out. Clear now?
Live as if you were to die tomorrow. Learn as if you were to live forever. - Mohandas Gandhi
The OP could just start walking around naked in the house all the time. Then his wife would lose enthusiasm for having guests over.
Good decisions come from experience. Experience comes from bad decisions.