I think they should if they can. Having been the bread winner for a while, I have been in the situation where there was a very important meeting or project due. You kind of cross your fingers and hope for the best, hoping what you choose will benefit the ones you love. And you won't get fired, or lose the end-of-year bonus that pays off your credit card.
I would hope to trust my partner enough to be able to discern whether missing work would impact our lives in a stressful way.
When i was working I tried very hard to understand which was which.
I think my dh does the same. That said-- I have no reason to distrust his motives. He's always tried his best to care for us when i was not working. (and i did the same when he was not).
This is a tough one. Sometimes bosses suck really bad, and often companies do not care that there are actual humans involved in crazy working hours.
It comes down to whether I believe my partner cares for me, and/or our kids. Can he come home early? Can he check in with us at lunch? Can he go in a bit later? Will he call a relative to pick up some groceries for me?
If i believe he cares wherher i can manage, I would prob cut him slack. If, perhaps, my experiences have shown me he disrespects my needs , I would not cut him any slack at all. It simply depends on his basic character as a human being.
Only a partner can answer that. Does he want to help me get through a tought time, or does he want me to suffer?