While we may suspect that a divorce may be in the near future for Jack's parents as an excuse for their behavior is ludicrous...let's not forget the scars on Jack's back, thanks to his parents...anything else, no matter how it is phrased, or glossed over, or otherwise excused or ignored, can ever erase what they have done, or stood by while it was done...no matter the circumstances. Worrying that things may be getting worse at this point is akin to the ostrich pulling its head out of the sand...as to any sort of custody battle, with the truth out, both parents are losers...
To state that all may not be well with his parents' relationship is the understatement of the year, decade, and century...They both belong behind bars...
BTW...Jack isn't a trophy...he's a child...
In a sense, can we say anything is different for Nick, considering the loss of his father before and his mother essentially abandoning him, sacrificing him on the altar of the unceasing demands of work? Is that the only constant in his life to this point is his dog, Bojangles?
There are adult decisions that both Nick and Jack need to face if they want to have the relationship they both desire. It will require brutal honesty if they are to emerge from this as a couple...
Circumstances may be different between the boys, but in the end the results are the same for both of them...