Dear Jason:
So she does realize of late that it hurts you a lot when she talks to the other guy? And she promissed not to?

DId she express that she realizes that it hurts you before, promissed before not to talk to him and did it anyway?

Or did you have a more insgihtful conversation this last time where she had a new realization?

When you talk, do you listen to each other, applying EAR: Empathy, Assertiveness, Respect? How about discussing how to discuss, the rules (such as EAR) as preparation for more effective communication?

WHy does it blow over…Did you enjoy better communication in the past???

If you cannot manage effective conversations between the two of you, you might want to consider or re-consider a counselor, therapist.
anita