Assume they're living in a house and they have one child. Then:
$2800 for loans.
$3500 for mortage and escrow.
$1300 for child care (both work).
$1000 for food and day-to-day living expenses.
$1000 for utilities, Internet, services and recurring expenses --- parking, commute, health care copay and (with most employers) dependent coverage, etc.
I get $9600. Survivable? Of course. You can clearly survive in America with a $2800/mo student loan burden offset by a $200k/yr income. But:
* It's not "comfortable"; for instance, they aren't putting away money to put their kid in college.
* It's not resilient; they're fucked as soon as one of them loses their job.
* It's not flexible; for instance, they might literally not be able to afford to have a second kid.
Now, they don't have kids, I get that. But the moral of the story was, their student loan debt load was so high they couldn't stay married. They're smart enough to make 200k/yr, they're smart enough to do this math.