Act I: scenes 4-7

Ok, this may be a stretch, but hopefully its not. In the beginning of scene 4 Duncan is talking to Malcolm about the death of the Thane of Cawdor. The thane admitted to committing treason and just begged for forgiveness. Duncan then says "to find the mind's construction in the face: he was a gentleman on whom I built an absolute trust." I feel that Duncan was betrayed by this Thane of Cawdor, then he appoints Macbeth the new Thane of Cawdor. I find this may go along with the theme of doubles because his view on the Thanes of Cawdor is the same both times, and both times he's betrayed by them. And after Duncan says its weird how he could never tell by Mcdonwald's face that he was being betrayed by him, Macbeth walks in and he praises Macbeth by saying "o worthiest cousin!" So I feel that Duncan is falling into the same betrayal from before. Now I'm not sure if this would fall under the theme of doubles, but I think that it does and I find this very interesting that he was betrayed by different Thanes of Cawdor twice. Maybe he should have ended the title "Thane of Cawdor" to end the backstabbing, but he didn't, so he will die.