Matthew 1:25
καὶ οὐκ ἐγίνωσκεν αὐτὴν ἕως οὗ ἔτεκεν υἱόν· καὶ ἐκάλεσεν τὸ ὄνομα αὐτοῦ Ἰησοῦν.
And not knew her until which gave birth to son, and he called the name his Jesus.
Again, context is your friend.
‘Until’ in the bible does not always mean the activity before stops afterward.
1 Cor 15
[25] For he must reign, until he hath put all his enemies under his feet.
Context is indeed my friend, unless you believe that Jesus stops reigning after His enemies are under His feet.
See also:
“As it is written: God hath given them the spirit of insensibility; eyes that they should not see; and ears that they should not hear, until this present day.” (the not hearing and not seeing does not stop that present day)
[Romans 11:8]
and:
“We are blasphemed, and we entreat; we are made as the refuse of this world, the offscouring of all even until now.” (again not stopping now)
[1 Corinthians 4:13]
and:
Acts 2
[34] For David ascended not into heaven; but he himself said: The Lord said to my Lord, sit thou on my right hand, [35] Until I make thy enemies thy footstool. (Still sitting at the right hand afterwards)
and:
“And Paul looking upon the council, said: Men, brethren, I have conversed with all good conscience before God until this present day.” (Did Paul never again converse with good conscience?)
[Acts Of Apostles 23:1]
My friend context shows me that it is perfectly biblical to believe that Joseph’s behavior (not knowing Mary) continued after the birth of Jesus.
Love,
O2
Also, extra-ordinary claims require extra-ordinary proof, of which none has been shown.