I dunno, I think I would see what he says and ask him about the other relationship... I would make sure that he knows what it was that was a "fail" in this process and then play it by ear. Being new to poly doesn't make the person a failure at it when they first screw up... but it does mean they should learn from the experience.
I think I would let it go, not attach myself to any notion that anything will work out between me and him, forgive and see what he says... that way my heart would be open to possibility when I meet him rather than going to be closed and angry. If nothing else a friendship might come out of it.
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