Jansenism's views of marriage? What are Jansenism's views of marriage? Were they akin to Manicheans' and Albigensians'? Who was a prominent Jansenist who wrote about marriage?
The Jansenists were known for adhering to errors on grace condemned by Innocent X in 1568 (DZ 1092 ff.). Opposed to the Jesuits' presumed laxity, they were moral rigorists (&quot;hards&quot;), who, according to Noonan's Contraception p. 317,

insisted on the Augustinian tie between sexual acts, concupiscence, and original sin. They [unlike St. Augustine] insisted on the sinfulness of initiating intercourse with any purpose other than procreation.

Thus, the Jansenists appear to have an extreme procreative view of sexual intercourse. The Cathars / Alibegensians were against procreation because, like the Manicheans, they believed the material/bodily world is evil and that marriage is, too, because it &quot;traps&quot; souls in bodies.
Catholic teaching is that (Summa Theologica suppl. q. 49 a. 5 co. // Super Sent., lib. 4 d. 31 q. 2 a. 2 co.)

when married persons come together for the purpose of begetting children, or of paying the debt to one another (which pertains to &quot;faith[fulness]&quot;) they are wholly excused from sin.[quando conjuges conveniunt causa prolis procreandae, vel ut sibi invicem debitum reddant, quae ad fidem pertinent; totaliter excusantur a peccato.]

Martin de Barcos, a student of Cornelius Jansen himself, was a prominent Jansenist theologian. De Barcos promoted the heresy that &quot;St. Peter and St. Paul are the two princes of the Church who form one head.&quot; (DZ 1091). What he wrote about pleasure in marriage in Du decalogue pp. 296-301 does not appear to be contrary to Catholic teaching on marriage.
The Jansenist philosopher Pascal also seems &quot;to have an extreme procreative view&quot; of marriage when he writes (Pensées diverses III – Fragment n° 65 / 85):

les filles de Loth, par exemple, qui n’avaient que le désir des enfants, étaient plus pures sans mariage que les mariés sans désir d’enfant.the daughters of Lot, for example, who only desired children, were purer without marriage than marrieds who have no desire for children.

This statement depreciates virginal marriage.