While extra marital affairs do involve sex, research shows that sexual drive is not the main reason married men have affairs. You may be surprised what research shows.  
See article http://blogs.psychcentral.com/healing-together/2013/09/an-unrecognized-reason-that-married-men-have-affairs/?utm_content=bufferd5ed3&utm_medium=social&utm_source=facebook.com&utm_campaign=buffer