The answer is not complicated at all.
Matthew 1:24-25 Then Joseph being raised from sleep did as the angel of the Lord had bidden him, and took unto him his wife:
--The account declares that they were married: man and wife. He took unto him his wife. Couldn't be any clearer. Before that time, he was thinking of divorcing her.
25 And knew her not till she had brought forth her firstborn son: and he called his name JESUS.
--They had not yet had marital relations. They abstained because of Mary's condition, which of course, was from above, a supernatural condition. Joseph obeyed the Lord. But the verse says plainly that the marriage consummated physically after Christ was born.