I agree you have the right to be upset. It is not pleasant finding out about things about a spouse's past. People hard things for many reasons, but guilt and shame is a usual theme in most people's deception. Could she be ashamed of things she did in the past and that is why she never talked about it? We do stupid and things we regret as we go from teenager to adults.

Did you ever ask about her past, or did you assume she would share it on her own? Sometimes it is easier to forget things we regret, than dwell on our regrets of the past. There are several things I have done I wish I could undo, but the truth is you can't. It took me a long time to even tell my wife about them. It is expecialy difficult when you are held responible for those things and causes issues in the present. As difficult as it is for you to here those things she has done, it is probable just as difficult for her to accept and live with it.

I think most people try to portray the best in themselves, expecially to those we care about. It may be deceptive, but there isn't malice behind it, but it is out of caring and compassion for the other person. My advice is to talk to her and try to be honest. Finding out new stuff after 14 years is a bit of a suprise punch. I think you should just talk to her and tell her how you feel. You have the right to be upset, but I don't think we should be held accountable forever for a few misdeeds of the past. At the very least you deserve honesty and disclosure if you want to know, but once you know you can't forget it. Sometimes it is better to not know and leave it in the past.