So I was reading Matthew chapter 1 in Greek and I stumbled upon this little gem:
1.25 καὶ οὐκ ἐγίνωσκεν αὐτὴν ἕως [οὗ] ἔτεκεν υἱόν: καὶ ἐκάλεσεν τὸ ὄνομα αὐτοῦ Ἰησοῦν
That reads, in my own translation “And he did not know her (Mary) until she gave birth to a son: and called him Jesus”
So it looks like the straightforward meaning of this is that Joseph had sex with (i.e. “knew”) Mary after she had given birth to Jesus. Of course, there is a ready made apologetic for the plain meaning of this sentence, since Catholics have had over a thousand years to debate and prepare it:
Till she brought forth her firstborn son… From these words Helvidius and other heretics most impiously inferred that the blessed Virgin Mary had other children besides Christ; but St. Jerome shows, by divers[e] examples, that this expression of the Evangelist was a manner of speaking usual among the Hebrews, to denote by the word until, only what is done, without any regard to the future. Thus it is said, Genesis 8:6 and 8:7, that Noe sent forth a raven, which went forth, and did not return till the waters were dried up on the earth. That is, did not return any more. Also Isaias 46:4, God says: I am till you grow old. Who dare infer that God should then cease to be: Also in the 1 Maccabees 5:54, And they went up to mount Sion with joy and gladness, and offered holocausts, because not one of them was slain till they had returned in peace. That is, not one was slain before or after they had returned. God saith to his divine Son: Sit on my right hand till I make thy enemies thy footstool. Shall he sit no longer after his enemies are subdued? Yea and for all eternity. St. Jerome also proves by Scripture examples, that an only begotten son, was also called firstborn, or first begotten: because according to the law, the firstborn males were to be consecrated to God; Sanctify unto me, saith the Lord, every firstborn that opens the womb among the children of Israel, etc. Exodus 13:2.
The problem is that this makes sense if you assume the Perpetual Virginity of Mary from the start. But was that what Matthew intended? Matthew wasn’t a Catholic, so we have no idea whether he subscribed to the perpetual virginity of Mary, thinking of her as though she were some sort of vestal virgin. Maybe he put that in there to cement the idea that Jesus was born before Joseph had sexual relations with her.
Catholics, having syncretized a lot of their dogmas/traditions with the mores of the (pagan) Roman Empire, would be more likely to argue for that tradition based on being Romans. They would also have had traditions of aceticism since this undercurrent was around from at least the 2nd century; the idea of flesh and sexual relations being “sinful” inherited from the Gnostics and Marcion. They did get the basic layout of their NT from Marcion anyway.
There’s also no reason why Joseph would keep Mary around, being wed with her, and break the traditional Jewish requirement to be fruitful and multiply with his young nubile wife; Mary was probably around 13 or 14 when she gave birth to Jesus (assuming a modicum of the story is true). Joseph being a celibate, also, implies proto-Orthodoxy traditions of acetisim and not any legitimate (that we know of) early 1st century CE / late 1st century BCE Judaism.
Anyway, we should take Matt’s own writing in and of itself into account to determine what he meant. Earlier in the same chapter, a couple of verses before 25, he writes:
17 Πᾶσαι οὖν αἱ γενεαὶ ἀπὸ Ἀβραὰμ ἕως Δαυὶδ γενεαὶ δεκατέσσαρες, καὶ ἀπὸ Δαυὶδ ἕως τῆς μετοικεσίας Βαβυλῶνος γενεαὶ δεκατέσσαρες, καὶ ἀπὸ τῆς μετοικεσίας Βαβυλῶνος ἕως τοῦ Χριστοῦ γενεαὶ δεκατέσσαρες.
That is, “All of the generations from Abraham until David were fourteen generations, and from David until the Babylonian Exile fourteen generations, and from the Babylonian Exile until Christ fourteen generations.”
So what is the evidence we have? For one, we don’t know whether Matt was a Catholic, so apologetics from Catholic Jerome two centuries later might not represent what Matt himself was thinking. Second, Matt doesn’t seem to use ἕως in other contexts to signify “never”. Third, the phrasing of the sentence seems to have been written to emphasize that Joseph didn’t have sex with Mary until after Jesus was born because Matt’s emphasis was on the virgin birth of Jesus, not the perpetual virginity of Mary. Mary all but disappears from Matt’s special material after this introduction, meaning that her role as the immaculate conduit for Jesus’ birth was over in Matt’s mind. If Matt had intended for Mary to be depicted as a virgin for the rest of her life, he might have mentioned it elsewhere.
Of course, none of this is intended to dialogue with Catholics. Just my own lucubration.