As a parent, spouse, employee, boss are they the same or different?
There is no LAW saying you must be faithful to your mate but isn't it an implied OBLIGATION?
Seems to me there are certain LOGICAL expectations inherent in all relationships whether stated or implied.
It is very confusing because the wiggle room allows for rationalization justification and wriggling out of something you SHOULD do. Homo saps are very good at doing that.