Hi Ann,
Mickey (welcome to Yedda !) gave you a very good answer (2 thumbs up).  I would like to add: It is clear from your notes that you love your husband, don't want to break your marriage, and want to help him, but at the same time can NOT tolerate his cheatings.  The best way to attend to your (his) problem is heart-2-heart, open and deep discussions. If you feel that you won't be able to do it on your own than better get a proffesional experience marriage counselling. 
Best regards,