They also aren't crushes at this point, let's be honest. This is a romcom where they are already largely with each other and friends are occasional (they act more married than most parents lol).
On the contrary, happily married couples are often some of the most socially isolated units that exist. You can certainly choose to remain social instead of getting married, but in such a case, relationships would be rather pointless. Funnily enough, the main characters act more married than most married couples we encountered as kids lol.
I would say you're reading too much into it, as this happens naturally and it's mutually beneficial. One man providing the supermajority of validation that one woman needs is not some malicious effort to socially isolate.
We are raised in a culture so devoid of discussing positive outcomes, that nobody takes that risk. Most of us are doing relationships wrong when we say healthy stages in relationships are "red flags".