What should a man do if his girlfriend of 6 years told him she was once a professional escort?

The girl im speaking of has a great personality, wonderful mother of 3 , but I cant seem to get the betrayal of her not telling me in the beginning or the start of our relationtionship.I mean why wait 6 years to tell me. I wonder if its embaresment of the fact she was once an escort or if there might be other underlying issues thats She is ashamed to tell me about.As far to date, she hasnt cheated on me but I just cant see the reasoning in the un-truths she has given me over the years. Can someone please give me some insight as to what i should do.