For many U.S. couples yearning to be married, the pandemic has wreaked havoc on their wedding plans while bolstering their teamwork and resilience. For couples already married, it has posed a host of new tests, bringing some closer, pulling others apart.

Spending more time together — a common result of lockdowns, furloughs and layoffs — has been a blessing for some couples who gain greater appreciation of one another. For other spouses, deprived of opportunities for individual pursuits, the increased time together “may seem more like a house arrest than a fantasy,” suggested Steve Harris, a pr...