The production of Hormones is a natural physical process. God created our physical bodies and also designed in such a way that hormones be produced on a regular basis. Otherwise we would be without hormones. This is the reason why we get sexual urges right from the age our physical body reaches a level of growth and maturity. So, hormones are never from the devil neither their production is any temptation. Hormones are from our Creator.
This is very clear from the verse below -
Leviticus 15:16 - And if any man's seed of copulation go out from him, then he shall wash all his flesh in water....
Therefore, Sex is meant not only for pro-creation but also for enjoyment
within God's laws. This is again clear from the 2 verses below -
Ecclesiastes 9:9 - Live joyfully with the wife whom thou lovest all the days of the life of thy vanity, which he hath given thee under the sun, all the days of thy vanity: for that is thy portion in this life.
Proverbs 5:18,19 - Let thy fountain be blessed: and rejoice with the wife of thy youth. Let her be as the loving hind and pleasant roe; let her breasts satisfy thee at all times; and be thou ravished always with her love.
Sex is a natural physiological urge similar to the urge to urinate or the hunger to eat or the thirst to drink. To urinate, eat or drink is not the only goal in life. They are part of our everyday living. Similarly, Sex is supposed to be a part of our life and not the only obsession. When sex becomes the only obsession then it becomes Lust as defined in the Bible.
Sex is not the ultimate goal. Spiritual Development is the ultimate goal. Sex can also play a positive role in our Spiritual Development process although it is mostly mistaken that it plays only a negative role.
To have sex before marriage is entirely an individual choice of the person as God has given freewill to all His children. Some may not prefer pre-marital sex whereas some others may not be able to exercise self-control and might prefer to release their sexual tension. It is really upto each individual to think and decide what is good for him. Personally, i tend to encourage those who prefer to keep their virginity until they get married and i am sympathetic to those who were not able to control themselves before getting married.
I must also add that for those who involve in sex with multiple partners, there is always the danger of getting Sexually Transmitted Diseases or even AIDS.
I would like to suggest a few useful links on this topic -
1) Sexual Ethics for all of us -
http://www.whosoever.org/v2Issue2/ethic.html
2) Sexuality and Spirituality -
http://www.theuufellowship.org/_sermons/030216.htm
3) The Christian Enjoyment of Sex -
http://www.thebodyissacred.org/body/sex_joy.asp
:-D