The affirmation is nice and yes, addressing the comment will bring on all kinds of emotions that really they've dealt with in as much as they're likely to be dealt with. Rehashing those won't do anything for either of them really. Shocked and a little angry despite knowing she's got no right to either of those reactions, yes. She knows his life didn't start the day he met her but most of the time it's not in her face quite so much. In this case, yes, the presence of said children does make this sort of thing necessary. They handled it fairly well though, or so it seems.

"She's bits of you. I get along with and even love all the bits of you."