Edward,
There is only one thing wrong with what you have said, sex is not love. Love is a decision to share one's life resulting in a, planned, life long union of a man and a woman, Sex on the other hand, contrary to Hollywood's teaching, is a product of one of two causes;
1. lust or
2. a well founded marriage where both, man and wife, work to satisfy the physical and emotional needs of the other.
The difference in the length of the answers of one and two do, coincidentally, illustrate how long both last in the life of a person. And, much, to the distaste and disbelief of most of the world, the back seat is the world's worst invention any human ever created. Every time a male and a female human crawls into the back seat and couples, they are, in the eyes of God, married and almost all of those unions fail, resulting in an undocumented divorce.