First of all being a Private Investigator is not like it is portrayed on TV. The reality of it is the client hires you for a reasonable hourly rate. Well as being a PI you know they are paying a decent amount of money upfront usually and the client thinks it will happen right away catch the smoking gun. Well after 10 or 12 hours and usually a $1000 up front you might not know any more than you did when you started. You are not always in a place that is too your advantage to see everything when they leave work or go to work, they might of been tipped off by the spouse that they hired a PI than your work is 10x as hard.
So the client is still positive that the spouse will make a mistake and prove them right and they are going to be ecstatic you caught them. Well you will feel a bit of relief you did your job and their money was not wasted. But think again now reality peaks into the picture and they can not believe that however amount of time spent down the drain with the marriage and potential kids in the mix. I mean how many of us are going to say there you go they have been cheating aren't you happy? It is not reality and I guess if you have a heart you kind of feel worse than than if you didn't. This is a double edged sword but as Private Investigator doing your job is not always glorious as it is portrayed in the movies.