Behavior patterns are generally unwritten and constantly changing.
There are considerable differences between social and personal values.
Thus, the concept of marriage is changing widely in many countries.
For example, director Blake Edwards wanted to date singing star Julie Andrews, and he joked in parties about her persona by saying that her "endlessly cheerful governess" image from movies such as Mary Poppins and The Sound of Music gave her the image of possibly having "lilacs for pubic hair"; While the term dating has many meanings, the most common refers to a trial period in which two people explore whether to take the relationship further towards a more permanent relationship; in this sense, dating refers to the time when people are physically together in public as opposed to the earlier time period in which people are arranging the date, perhaps by corresponding by email or text or phone.
Cars extended the range of dating as well as enabled back-seat sexual exploration.
In the mid-twentieth century, the advent of birth control as well as safer procedures for abortion changed the equation considerably, and there was less pressure to marry as a means for satisfying sexual urges.
As humans societies have evolved from hunter-gatherers into civilized societies, there have been substantial changes in relations between men and women, with perhaps one of a few remaining biological constants being that both adult women and men must have sexual intercourse for human procreation to happen.
Humans have been compared to other species in terms of sexual behavior.