I suspect that you're correct that Stan doesn't know why he wanted to be with Sandra. That's so tragic, though. When he was with Nina, I always questioned if he truly loved her or if he just loved the weird situation she was in (spying on her own team for him).

You're correct about Elizabeth: she wants to be the perfect, unflinching soldier but she also is strangely vulnerable and needs to have her choices validated. I don't think she can comprehend how Philip could chose family over duty. The concept is alien to her. I agree: It's got to be painful for her to cling to the idea that the State trumps all other aspects of her life, including her own emotions and needs. When she talks about her feelings, it is Elizabeth the Spy talking, not simply Elizabeth. Her own emotions and needs frighten her.