Jennifer Lopez and Alex Rodriguez reaching a breaking point came as a total shock to their kids -- and that's one major reason the couple's together right now in the Dominican Republic trying to patch things up.
Sources close to the couple tell TMZ ... neither of them expected news to break on Friday about their split, and as a result, they didn't have time to prepare their 4 children ... who've all grown very close.
We're told J Lo's 13-year-old twins, Emme and Max, and A-Rod's teenage daughters, 16-year-old Natasha and 12-year-old Ella, were all devastated by the discussions the modern family had on Friday of a possible break up.