Well, it seems that your fiance is a bit overbearing and it seems like you yurself can't handle it. From what I can see your relationship won't last long with the way you both are. She has a strange sense of needing to "know" and you aren't serious and don't have enough feelings for her. The answer is already there, if you felt a deep connection to her you would have just asked what can I do but instead you thought of it as a decision of let her go or give in. I don't mean to open old wounds or anything but it seems if you had a problem in your last marriage what makes you think the new marriage will last with those reckless feelings.