A courtship ideally ends up in a marriage and hopefully a happy one.
In Malaysia the divorce rate is high and I believe this trend is similar in most developed nations.
“The number of divorces in Malaysia has more than doubled in just eight years from 2004. In 2012, a whopping 56,760 divorces were recorded, which is equivalent to a marriage breaking down every 10 minutes.”
Many who are still together are together for reasons other than affection.
There are many external factors that could affect the relationship but this is, I believe is not the main factor that could cause it. It is usually the internal factors. Internal factors of character as well as Destiny.