It's possible that he may not have been thinking very straight with the separation from his wife. I have seen men do some strange things when they are going through a seperation, especialy if it is at the behest of their partner. Under these circumstances, a whole cocktail of emotions can do strange things to their brain. The normal thinking process is thrown out the door.
But maybe he has being dealing for a while, didn't get caught, and assumed he could get away with it forever.
