You start with going NO CONTACT. If you say you can't because its through work, then you are already choosing the affair over your marriage.
Affairs are an addiction. They set off pleasure chemicals in your brain. True fact. That is why its so freaking hard to cut off and affair. Best is cold turkey.
Second tip for success is confessing your actions. That will serve to get your husband to know what you have done and keep tabs on you. But doubt you will do that.
If you chose the affair you must know, YOU WILL GET CAUGHT eventually. This has to be something you accept. If this is an exit affair and you already wanted out, leave just do it. **** or get off the pot.
But know, that affairs are secret for a reason.... You don't ever REALLY want to be with that person. You only see him at his best, and he only sees you when you are at yours. Your affair person i bet has never lanced a boil on your ass, and you have never helped him with a terrible ingrown toe nail. As a woman married 10 years i am sure you have a story or two about something your husband helped you with or vice versa. This other man has three kids, Are you ready to have a brady bunch house hold?
Speaking of kids, Have you put much thought to your kids lives being turned upside down? or the fact if they are old enough could think you betrayed them and the life they thought they had. Maybe even change their beliefs and views on love?
Think REAL HARD....this other man is not worth destroying your kids lives over, This other man is not BETTER than your husband. If your husband isn't beating you, and is in all there for his family and is faithful he is absolutely BETTER than this other man. Why? Because he chose you. He stood by you.... What have you done for him lately?
I may be harsh here but i really hope and wish you the very best. Good luck . its a hard choice, but you already know what is right for you and your family.