The whole culture has shifted on sex matters. People have always had sex, and did so outside marriage before we had birth control pills. But the culture was different then, and if any accidents happened, often couples would get married. Nowadays you rarely see such weddings because of a pregnancy.
It would be interesting to have discussions about the overall impacts on society of birth control and the whole sexual revolution and change in attitudes surrounding sex.
Well, for thousands of years, couples who had had enough kids and didn't really want more had probably discovered all of the whiz bang 20th century stuff. I'm just guessing. But a generation of people became convinced that they had discovered a whole new world and they all felt obligated to obsess over it.