God invented the idea of FAMILY. Adam and Eve were told to be fruitful. Sex was for use within the idea of family. Those who decided not to marry and have a family should not use sex for pleasure or other purposes. Get married and have all the sex you want.
This is a very valid point. Sexual sins outlined in Israel were mostly of the kind that were indulged in outside of marriage....it was for the sake of pleasure only, with no commitment. This never had God's approval.
And you are correct about sex being the means to increase families.....children born, had a right to a family....a mother and a father to balance gender roles, (so out of whack now) and a secure and loving family in which to grow physically, emotionally and spiritually. Having only one sexual partner protects us from sexually transmitted diseases. Having multiple partners is the cause of STD's.....so our bodies are designed to become "one flesh" with one marriage mate for life.
Choosing the right marriage mate is what is recommended in the Bible. Being "past the bloom of youth" will mean more mature choices. Sex is a lousy reason to get married. If two people are compatible in other more important ways, then the sex will take care of itself. Once the honeymoon is over, incompatibility in other areas almost always leads to emotional distancing or divorce. It stands to reason that lasting relationships are not based on sex....which has little to do with genuine love (agape) anyway.
In the Greek there are four words for "love"....
, phi·liʹa, stor·geʹ, eʹros and a·gaʹpe.
"Phi·liʹa"...is brotherly love.....brothers and sisters in our spiritual family and friends
.
"Stor·geʹ"...is love among blood related family members.
"Eʹros"....is romantic love between the sexes....the subject of "love songs".
"A·gaʹpe"....is the most important love of all...it is love based on principle....one that doesn't not allow hatred to rise up even under provocation....the one that can be applied to even an enemy. This is also the most difficult one to master.
Interestingly, eʹros is not even mentioned once in the Greek scriptures.....so its not high on the list when it comes to expressing love. Perhaps now we know why sex is not a good basis for any lasting relationship.
Celibcy in the Bible is a recommendation for those who wish to serve the Lord undistracted by the needs of a mate. There is no shame in marriage, but Paul was stressing the freedom of being able to serve God wholeheartedly. It is for those who can "make room for it".