it was claimed sunday that the food network star has been cheating on his wife with assistant elyse tirrell for three years .
flay 's business partner lawrence kretchmar dismissed the report , saying he 'd have known if the chef was having an affair with an employee .
tirrell , who is 28 , used to work as a hostess at one of flay 's restaurants before being promoted to be his assistant .
the celebrity chef has filed for divorce from march , 40 , after 10 years of marriage but she is contesting their prenup .