I dunno, I really think he did love Cally. I just think that this is the most...gross act ever to commemorate that. And that he abandons his son despite the hopeful note in the actual episode where Nicky's paternity is confirmed making it seem like he's not going to. Basically I think he does it because he's totally frakked up. And his killing of Tory is another testament to that. But...apparently one we're supposed to approve of. *sigh*