Joseph Ratzinger, "Zur Frage nach der Unauflosigkeit der Ehe," in Ehe und Ehescheidung
(Munchen: Kosel, 1972), pp. 55-56:
The anathema [of the Council of Trent] against a teaching that claims that foundational structures [forms] in the church are erroneous or that they are only reformable customs remains binding with its full strength. Marriage is a sacrament; it consists of an unbreakable structure, created by a firm decision. But this should not exclude the grant of ecclesial communion to those persons who acknowledge this teaching as a principle of life but find themselves in an emergency situation of a specific kind, in which they have a particular need to be in communion with the body of the Lord.
transl. from: Ladislas Örsy, S.J., Marriage in Canon Law: Texts and Comments, Reflections and Questions
(1988), p. 293.
This sounds like Amoris Lætitia
§301: "A subject may […] be in a concrete situation which does not allow him or her to act differently and decide otherwise without further sin."
People doesn't just happen to "find themselves in an emergency situation" (state of sin); they place themselves therein!