Her getting her face touched by a crush from before you dated, has NOTHING to do with you in any way, shape, or form. She was single, she owed no one any "loyalty" whatsoever. You're taking a miniscule event and making it about you rather than some fleeting thing she experienced. Frankly, it was none of your business that it even happened. You need to let her know how much this event has effected you and talk it out with her. You seem to be dealing with some jealousy.