This is really good advice, thank you.

Remember that she has given you no reasons to distrust her, and whatever she may or may not have done in another relationship has nothing to do with YOUR relationship together.

While she hasn't done anything major to make me distrust her, I do believe that if she had cheated in the previous relationship right before me I wouldn't be able to continue dating her. I know she didn't straight up cheat but if it was something that could be considered borderline by the court of public opinion, I would want to know. If she did do something borderline than I think it would be a good learning opportunity for us without actually going through the anguish of experiencing it.

If the reasons she gave didn't explain her ex's behaviour than I feel like it would be a great opportunity to strengthen the relationship and her confidence by telling her she didn't do anything wrong.