You have every reason to feel anger, disgust, mistrust...esp if you feel you were deceived.

I am still unclear as to why this came up out of the blue (after 14 years). Were you probing, sexting, playing 20 questions...did she casually "confess"?

What is your biggest concern / fear ... now that you have this info? Are you seeing her differently? Do you still respect her? That is the main thing.

It appears you don't trust her any longer. That leads to a multitude of problems in any relationship.

Have you told her how you feel? I mean, how you really feel?