Sometimes I've got this feeling that Jerry (Liam Neeson's character) was devoloping feelings for Nell. Also Paula talks about that: "why do you think you spend so much time with her?"
Maybe I'm completely wrong, What do you think about this?
When Paula mentions the part about Jerry spending time with Nell- she doesn't mean it in a "sexual" contexts. She means that Nell is "perfect" because she's non-threatening and Paula has picked up on Jerry's fear of women that he perceives as threatening (Paula's character) since his divorce (which is mentioned in the beginning).
So much of this movie's back story is just mentioned in passing during conversation.