Nothing in the chapter addresses fiance's, only those who are already married.
Mary and Joseph were both Jews, and would have become betrothed (ie. engaged, promised one to the other to be married), according to Jewish customs and traditions.
This link gives a fairly concise rendition of the betrothal and marriage, per Jewish customs.
10.1. The Jewish Wedding Analogy Commentary - A Testimony of Jesus Christ
During the time of the wedding Mary is a virgin.
After the wedding ceremony Mary and Joseph are thus Married (ie espous
ed), and Mary is still a virgin.
Typically after the couple are Married, they go to the chamber prepared by the man, and consummate their marriage, by lying together.
Then there is a feast.
There is no detailed record of WHAT did happen in the marriage chamber - but what did not happen is they did not lie together. And shortly thereafter the wedding day, Mary went to visit her cousin Elizabeth for 3 months, then returned home. Joseph in the meantime was conflicted over marrying a woman who was pregnant, and what to do about it, yet Scripture continues to indicate Joseph provided for Mary, his wife's needs, but was not sure how to put her away from him, as his wife.
Then comes the time nearing for Mary to deliver, and also the time, people had to go to Bethlehem to declare their poll tax, (a tax upon persons). Joseph took himself and his wife to Bethlehem and declared them husband and wife, according to the law.
An angel appears to Joseph in a dream and says;
...Joseph, thou son of David,
fear not to take unto thee Mary thy wife: for that which is conceived in her is of the Holy Ghost....And she shall bring forth a son, and thou shalt call his name JESUS: for he shall save his people from their sins.
Thereafter, Joseph, accepts Mary as his pregnant virgin wife, and honored her virginity until after the child was born.
Matt 1
[
24] Then Joseph being raised from sleep did as the angel of the Lord had bidden him, and
took unto him his wife:
[
25] And
knew her not till she had brought forth her firstborn son: and he called his name JESUS.
Mary was by the time-line of scripture, a virgin when she was betrothed to Joseph, a virgin when she married Joseph, Learned of her pregnancy right after they were married, and did not lie with Joseph, her husband, until after the baby was born.
Luke 1
[
27] To
a virgin espoused (married) to a man whose name was Joseph, of the house of David; and the virgin's name was Mary.
[
28] And the angel came in unto her, and said, Hail, thou that art highly favoured, the Lord is with thee: blessed art thou among women.
[
29] And when she saw him, she was troubled at his saying, and cast in her mind what manner of salutation this should be.
[
30] And the angel said unto her, Fear not, Mary: for thou hast found favour with God.
[
31] And, behold, thou shalt conceive in thy womb, and bring forth a son, and shalt call his name JESUS.
[
32] He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David:
[
33] And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end.
[
34]
Then said Mary unto the angel, How shall this be, seeing I know not a man?
God Bless,
SBC