Thank you for asking this question. It is unclear from your email if these relationships happened before you two were together or if she had sexual relations with these men WHILE you were dating. This makes a big difference on how you approach it.
If these relationships were before you met, then the work is for you to learn to accept she had a life before you. This may be difficult to accept and work through, but the strength of your relationship and the promise of a future together will help you work through it.
However, if she has been with the two men AFTER you thought you were exclusive, then it is time to be thankful you learned about her character now before you married. If she was unfaithful with two men in this way, then you will want grieve what you thought you had with her and move on.