I used to find it odd that doctors would order a "stress test" for an individual who was thought to have a potentially weak heart. My thinking: why weaken it or, worse, cause a heart attack. Doctors' thinking: exactly!
As you are probably too well aware, many people do have a cardiac event on that "dread mill" and are admitted right away to ER.
Stress tests of aged, yet active bridges and overpasses are different- but the concept is still the same: engineers want to reproduce an extreme situation whereby the structure will let them know it needs partial repair or a complete replacement either now or years from now.
Similarly, COVID might be considered a kind of stress test. From already failing businesses to superficial relationships, things that probably needed to "go the way of all good flesh" (as my wry college philosophy professor would call death), just seemed to disappear.
Any outside threat, challenge or obstacle is an opportunity for an individual or a couple. It tests your mettle. It will make you pause and talk; consider action or not; make plans or change course. But make no mistake: it will make you stronger. I know that's such a cliche, but tell me it's not true. Notice I didn't say "it won't make you wince a while or limp a little..." that might happen in the process. But if it's true that Everything Belongs, then how you confront the toughest thing in front of you right now is illustrative of the strength you bear for the long haul. Keep training!