Vijay and Tammanah's story in Lust Stories

It just made no sense whatsoever. Was he always planning on killing her? If she was leaving him alone with his new found rich wife. And she was living her own life. What was the problem? I can get the motive to kill her after she discovers the truth. But why was he so persistent to follow her into her home when he found out she was living? There wasn't even a wee bit of shock in his expression.