Instead my head is somewhere else entirely, and I might have been annoyed at myself for forgetting to pick something up at the store or whatever.
We've gotten better at handling it, I try to remind myself to immediately tell her it wasn't her, and she asking me what it was if I forget. But there has been a lot of unnecessary bad times that originated from such episodes...
This is not uncommon for men or woman to do, and more commonly expressed as ‘you are looking for things to point out’.
You can run your own little test. Convert the sigh to something similar like shrugging. Consider it debugging with console.logs until you find out the source of the bug.