We both get tested regularly and prefer partners that do else so. When I'm doing the bull thing, there is just something so hot about filling another man's wife with cum while he watches. Plus my wife loves the taste of pussy on my cock when I come home.
As for the wife, she loves cum. Her idea of a perfect hotwife evening is another guy and me each leaving a couple loads of cum in her. For my part, I enjoy the warm silky smooth feeling of fucking her messy used pussy for sloppy seconds or thirds.