I know I'm probably supposed to be on Libby's side here because it sounds like Sam was an unforgivable jerk 12 years ago. Even though I think she has a right to her anger she is annoying as all hell. I kind of feel bad for Sam because she's so unreasonable. And now she thinks he owes her an apology and explanation for his son? Uh, no. The way she's acting it shouldn't be a question why he didn't tell her about him.
ETA: And, thankfully, she just figured it it out.
"She remembered Sam showing her the plans for the pavilion, and the way she had
brushed him off; Sam coaxing her down to pizza and karaoke night, only to have
her self-righteously proclaim that she needed to work; Sam asking her for
guidance in learning the job, only to have her try to dissuade him with
. . .
'Oh, crap. I have been such a bitch.'”
So, we're all agreed then.