I could understand Greg's frustration with Kevin
I could understand his feelings of inadequacy. My now ex boyfriend, had an ex wife with whom his parents are still very close with. Granted, they had grown children together, but I always felt shoved to the side by their ongoing affection for the woman, and I was treated as less than human at times. One of the reasons we are no longer together is because of his family.
And like Kevin, my boyfriend's ex still also had unresolved feelings and issues with him, and would call at least once a week just to talk.