I've never worked with a significant other, but I'd imagine it comes with some general concerns. That is, unless you're Zendaya working with Tom Holland on Spider-Man, in which case the fear is ultra-specific: Yup, that Tom might choke on his own vomit in his Spidey suit.
Speaking on The Graham Norton Show, Zendaya explained how stressed out she'll get watching Tom on set sometimes. She began by saying that the suit is, "One piece — there's a helmet, and there's all these things that go underneath it."
"I always have this fear that if he's working really hard or something's happening — if he had to throw up, per say, how's he going to get it out?"
"This is a genuine concern! Sometimes when I look at him I get a little scared — it just stresses me out!" she added.
As for Tom's response? Yup, it's to troll Zendaya — sometimes he'll pretend to wretch in the suit, which will trigger a, "No, help him!' response from Zendaya.
That being said, it didn't look like Tom was actually too upset to have Zendaya fretting over him:
For what it's worth, this isn't exactly a new concern from Zendaya — she's been expressing this since at least 2019: