Maybe he didn't know she was calling that guy? We know she was afraid of him, but to what extent it's hard to say. Maybe she was trying to invite the guy for insurance, just in case KY tried to do something someone else would be there and KY couldn't reject the guy because they were friends. Hard to know what happened there. Sociopaths are in some ways childlike because they don't have the capacity to process or even feel emotions beyond a superficial level. If he's a sociopath, he wasn't really dreaming about the white picket fence and fairy tale ending like most people who are truly in love would. He's sort of copying what he sees others doing that he thinks is a normal way to act. For a sociopath, it's about control, not love, and it seems his form of love was obsession. I think he was obsessed with her from the beginning. He saw her good heart and open personality and saw it as an opportunity to control and manipulate. He's scum, a monster, regardless of any professional diagnosis he may get. I too think he will continue with the whole "i don't know what happened, i had nothing to do with it" crap. It's worked for so long, why stop now.
