The amount of times I've seen people on this sub seemingly have no concept of love/morality/empathy. You see characters getting judged entirely on the consequences of their decisions as if, just because they are nobles, they aren't also people with feelings and values which give reason (even if it's not always a good reason) to their decisions. I don't recall feeling like Catelyn was colder towards Robb in any way after he brought Jeyne back. If anything, I'd argue that she might have felt more motherly love because:

a) it was a stupid thing to do, which highlighted how young and in need of guidance Robb still is

b) it was a noble thing to do (the marriage part, not the bit that led to it), which she'd be somewhat proud of him for, even knowing it's a bad decision.