Goofs

When Grace gets out of bed to see where Shannon is, she puts slippers on, but when she's seen walking down the stairs she's barefoot.

Officer Bryant handcuffs and arrests a suspect on the hood of his police car, receives an urgent message, then tells suspect to "stay right there" he drives away leaving suspect still handcuffed. The same exact situation is repeated 5 min later when looking for his wife.

After he arrives at Sarah's house, a fight ensues he handcuffs her and says "stay right there" then continues his search.

On multiple occasions during the diner scene the extras can be seen looking directly at the camera and actors, and pretending to eat and drink even when it is obvious to the viewer that there's no food on their fork.

At 42:00, Grace receives a new text message from Shannon while at work, but it's apparent that it's actually a photo depicting a new message notification in her photo gallery. If you look closely at Grace's photo gallery, there are other photos of similarity.

At 1:02 when Shannon turns to leave the room, a wireless microphone transmitter is visible on his back.

Shannon received 11 blows to the back and side of his head from Grace (9 by force) with a baseball bat while seated when she learns of his deceit. It is unexplained how he survived that attack when he re-appears toward the end of the film to try and subdue Officer Bryant inside the house.

While Sarah is making tea, the shadow of the boom mic is visible on the cabinets as she moves around.