So he and she.....

. Mental image wasn't needed.
If he has no emotional attachment he should boot her out. If there is attachment then do the prenupt thing and marry her.
As for his immortals soul feel free to remind him that Americans have made it a national pass time to do the opposite of this little commandment anyway.
Thou shalt not covet thy neighbour's house, thou shalt not covet thy neighbour's wife, nor his manservant(lawnservice), nor his maidservant, nor his ox(SUV), nor his ass(lawnmower), nor any thing that is thy neighbour's.
So spiritually Americans are f***ed anyway.