I am sorry to read about your predicament.

You have one of two choices in this case.

Let me mention the first and the ideal choice, which is to forgive, and continue the marriage. While saying this, I am assuming she has repented and changed.

It is a perfect choice – since you were wrong in digging into her past after tying the knot.  It is more like digging up a buried person. She was equally mistaken in divulging her past.  The Prophet (peace be upon him) said, “If anyone has been tested by indulging in any of the lewd and dirty acts, let them not lift the cover Allah has placed over them.” In other words, we are advised to repent and forget about our past sins; rather look into the future and never repeat those past mistakes.

Since you also violated the above principle, it is better for you to forgive her.  Allah wants us to forgive each other; when we do so, we have a better chance of being forgiven by Allah.

The other option is for you to divorce her. However, I would advise you against it. You cannot consider yourself wholly innocent or free from sins: Your act of digging into her past was a sin, and the fact that you did bring up the issue after marriage and not before was also a mistake.

Therefore, I would advise you to forgive her and not break up your marriage.

For tips on how to foster a successful marriage, you may peruse the book: Blissful Marriage: A Practical Islamic Guide Paperback by Ekran Beshir.