I don't know what you mean by "way stricter." I have heard a number of Orthodox priests say that all marriage breakdowns involve a certain kind of adultery, or transfer of love and loyalty to someone or something else. In other words, they are somewhat flexible in the way they interpret adultery. I know a couple of Orthodox people who obtained divorce twice rather easily, once because of a wife's instability and violence, and a second time because of incompatibility. You are correct, however, on the 3-limit rule. The real difference, of course, is that the Orthodox Church openly treats the marriage breakdown and divorce as all-too- human behaviour requiring repentance and forgiveness. Even the second- and third-marriage ceremonies reflect this notion of repentance and mercy.