He's probably angry at himself for not saving Arpita's memories, and also at the fact that Aarti meant more to him than the memories... With the second reason I hope he gets over it as I would expect him to save anyone above some(special) memories, as otherwise he would seem very humane.
But the problem I have with this reason is that it doesn't justify his behaviour towards Aarti (obviously hardly anything would justify it, but I expected a better reason) and in fact it just made me feel even more sorry for Aarti.. The woman has just been through a terrible experience and here her husband is also putting her through more anguish, she could've died, but that doesn't seem to cross his mind.😕
Also how could Aarti forget that she could've died?😲😆
All week I was hoping that Yash is angry with himself and Aarti because he has fallen in love with her and he has finally realised it, but felt guilty as he thought he was betraying Arpita. And I'm still hoping that's part of the reason as it's the only thing that I believe could justify his behaviour a little.
On another note all the actors are doing such an amazing job. I'm glued to the show because of them.😊