The only part of the storyline that doesn't make sense is the fact that Sami is conflicted at all. KO has never shown any real care nor concern for Sami Zayn until there was a threat of someone else doing so. Up until Owens' constant meddling, Roman didn't have an issue with Zayn. After finally winning over Jey Uso, Sami was set to be in good graces with everyone in the Bloodline and have a "family." Now Owens has ruined all of that and really, it's somewhat out of character for Reigns not to seize upon that and hammer it home in Sami's mind. Kevin Owens has never been nice to him, not even when they were a "team" during the Shane/Daniel Bryan feuds.
If this were a real life domestic relationship Owens would be the bad guy because he's trying to keep someone else from moving on and being happy. The thought of Sami not always being around for him to randomly abuse and powerbomb into the apron is infuriating to him.