There was no full consensus on the doctrine of perpetual virginity within the early Church by the end of the second century, e.g. Tertullian (c.160 c.225) did not teach the doctrine (although he taught virgin birth), but Irenaeus (c.130 c.202) taught perpetual virginity, along with other Marian themes.[37] Origen (185-254) was emphatic on the issue of the brothers of Jesus, and stated that he believed them to have been the children of Joseph from a previous marriage.[45] However, wider support for the doctrine began to appear within the next century.[37]
Some writers from 4th century, Helvidius and Eunomius of Cyzicus (one of the Arians leaders), interpreted Matthew's statement to mean that Joseph and Mary did have normal marital relations after Jesus' birth, and that James, Joses, Jude, and Simon were the biological sons of Mary and Joseph, a view held by Helvidius and Eunomius.[46] Helvidius appealed to the authority of Tertullian against the doctrine of Mary's perpetual virginity, to which Jerome (c.340-419) replied that Tertullian was "not a man of the church."[47] Basil of Caesarea denied Eunomius' view since Basil sees Matthew 1:25 as evidence for, not against, Marys perpetual virginity.[46]
By the 4th century, the doctrine of perpetual virginity had been well attested.[48] For example, references can be found in the 3rd century writings of Hippolytus of Rome, who called Mary "the tabernacle exempt from defilement and corruption," [49] and the 4th century works of Athanasius,[50] Epiphanius,[51] Hilary,[52] Didymus,[53] Ambrose,[54] Jerome,[55] and Siricius[56] continued the attestations to perpetual virginity a trend that gathered pace in the next century.[6][7]
source https://en.m.wikipedia.org/wiki/Perpetual_virginity_of_Mary
Which only reinforces that Catholicism thinks sex with her husband is dirty and wrong and sinful. Otherwise her body would not have been considered defiled and corrupted by having normal relations with her legitimate husband.