I would'nt go to any extremes as myself & my wife have total trust in one another.
We always agreed that if one wasen't happy in the relationship anymore, we would rather sit down and explain our feelings rather than throwing yourself in the arms of a fling etc.
I believe that if i was to cheat or likewise my wife cheats, either one of us would be able to tell, as i would like to think that we know each other inside out ie tell tale signs, body language etc etc.
I appreciate that some people will say you can never trust someone 100% which i fully understand, but i'm sure that the majority of people know who to trust, some people could'nt smell a rat if it was placed under their nose.
Oh yea, if i or my wife cheated on each other, its game over i'm afraid, yes i do have children, and yes they will be hurt, but you have to set out your ground rules in your relationship, this is one of our rules, its been successful for 19 years, so we must be doing something right.