I think you're exactly right about this, but I do think that he's not just deceiving himself about the role the children play in this, either. My read is that becoming parents sort of originally sealed the deal on his burgeoning feelings for Elizabeth, back in the day, so it's all sort of one big blob of an Achilles heel for him.

And really, this is one of the only "real" things about their lives that grounds them and can't be taken away. For someone like Philip who can be such a slippery personality, having something that roots him (to use Elizabeth's great choice of words) would be a huge draw.

The center never should have had Elizabeth have children of her own. It's changing her.

I've wondered about this too. In real life there were illegals who didn't have kids (though there were of course some who did too). I imagine that they must have discussed that; weighed the pros and the cons.

It's such a great scenario to have them have kids because on the one hand, who knows how much earlier someone might've gotten suspicious of them if not for the presence of kids continually working in their favor to present an image that was the opposite of "spies" in their minds? But on the other, it's a risk to bank on the idea they won't get attached to their kids and bond as a family. Sure, some people don't, but most do.