Every culture is different in their views of sex, marriage, age of consent, girls/women, morality, etc. Despite that, there are many commonalities also.

For most cultures, the purpose of marriage is to have children and carry on the traditions and language of the culture.

In Europe, for example, the purpose of a princess is to bear male children for her husband regardless if he is a king, prince, duke, baron, knight, etc. Especially in the case of a princess marrying a prince and eventually becoming the queen after her husband ascends to the throne. In this case, the queen may become a liability, especially if her father or brother is a rival king. Imprisonment and even assassination could be the fate of the wife a paranoid king. It was rather common for a princess to be part of a peace deal and given in marriage to a rival king or his son. In that case, the princess would meet her husband for the first time when they meet at the altar.

The story of Queen Elizabeth I of England is a tale of sexual politics:
From the start of Elizabeth's reign, it was expected that she would marry and the question arose to whom. Although she received many offers for her hand, she never married and was childless; the reasons for this are not clear. Historians have speculated that Thomas Seymour had put her off sexual relationships, or that she knew herself to be infertile. She considered several suitors until she was about fifty. Her last courtship was with Francis, Duke of Anjou, 22 years her junior. While risking possible loss of power like her sister, who played into the hands of King Philip II of Spain, marriage offered the chance of an heir. However, the choice of a husband might also provoke political instability or even insurrection. https://en.wikipedia.org/wiki/Elizabeth_I_of_England#Marriage_question
In the film "ROB ROY", James Graham, 4th Marquess of Montrose, ponders the health of Elizabeth. He remarks, "One would think that a field so well plowed would yield one good crop."

Again, I can only speak of my cultural norms and of those that I have read about. I remember a long while back, the news broke out that one of my female cousins wanted to leave home and get her own apartment. While that may be admirable now, my father was rather upset about the whole thing. This was not "normal" and it was seen as "immoral". While else would a young adult female wish to live alone? Obviously, so that she could have men over and have sex!

Again, according to family tales, just because you assume the role of lady of the house after the first wife dies, does not mean that you will be respected in that capacity, especially if your eldest step daughter is the same age as you.

The answers to your questions will differ from culture to culture. There is no one correct answer.