ISB ~ Matthew 19 v10

not expedient to marry:The disciples marvel that Jesus prohibits divorce and remarriage in the New Covenant (19:9), reversing the long-standing permission of the Old (Deut 24:1-4). Their incredulous response makes it certain that Jesus permitted no exceptions for husbands and wives bound together by the sacrament. This new and higher standard leads them to see the comparative superiority of lifelong virginity to married life (CCC 1615).