A very good question. I’ve never understood why Catholics are so intent on Mary’s being ever virgin.
It seems to imply they think her living in this regard as a normal woman would denigrate her. What I don’t understand is why they think this way. Why would a Mary who had intercourse with her husband after the birth of Jesus be any less admirable or worthy of veneration? Are we supposed to think there is something shameful about this entirely normal and righteous act?
Have never gotten this.
“...never understood why Catholics are so intent on Mary’s being ever virgin...”
It is because of the importance of Mary’s holiness because her body must have no contamination because of Jesus’ perfection.
The Blessed Mother is the Ark of the New Covenant. The previous Ark of the old Covenant was the dwelling place of God and the Ark of the New Covenant, Mary is also the dwelling place of God. (Luke Chapters 1 and 2)
The orginal ark contained in the tabernacle was the Holy of Holies and to touch it was to die. It was a type or figure of Mary who became the new tabernacle containing God. Mary was overshadowed by the Holy Spirit and so permanently changed by this overshadowing; She must remain undefiled by sinful man afterward - she became too perfect for ordinary mortals to “touch” in that way.
The Ark of the Covenant could not be touched - however it was not worshipped, and Mary is not worshipped, either. We love and admire her perfection but do not worship it.
In other words, it is because of Mary’s perfection as the new tabernacle that she must remain so. All of the scriptures in the Old Testament that describe the Ark of the Covenant and the Temple are the biblical references for this teaching as they describe the type or pre-figurement of the perfection and worth of the coming new testament ark - Mary.