Dark Harbor - what about the watches?

hola folks, I've just re-watched Dark Harbor yesterday night and there's this scene shortly before the climax, when Alexis checks the time on David's watch. David seems kind of pissed of o even alarmed that she isn't wearing her own watch because she usually always wears it. Did tu understand why she isn't wearing it o why this seemed to be a problem for David?
And shortly afterwards the unnamed young man says he likes David's watch. There has to be a special meaning behind this statement, hasn't it? Can tu help me there?