"For this is the will of God, your sanctification: that you abstain from sexual immorality; that each one of you know how to control his own body in holiness and honor, not in the passion of lust like the Gentiles who do not know God."

-1 Thessalonians 4: 3-5 

These days, many people are having sex outside of marriage, and society says that it's 'okay'. Society also says that virgins (people who have never had sexual relations) are prude, uptight, and "not fun". 

However, the Bible makes it clear that virginity until marriage is the best way to go:

"Flee from sexual immorality. Every sin a person commits outside the body, but the sexually immoral person sins against his own body."

- 1 Corinthians 6: 18

Sex that is outside of marriage is also catering to the desires of the flesh. Remember how Matthew 26: 41 says "the flesh is weak"?

"We are in a contest between our new nature in Christ and our fleshly desires."

- Ephesians 6: 14

When we give into the fleshly desires, we are disobeying God. However, with sexual immorality, there are some clear consequences, such as the more commonly feared STDs and unintended pregnancies. However here's another consequence that plagues society:

Premarital sex actually violates the sanctity of marriage. The purpose God has given sex is to procreate and strengthen the union between a man and a woman:

"For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh."

- Ephesians 5: 31

When people have sex before/outside of marriage, they are forming a connection with someone who is not wholly committed in a lasting relationship.

Fulfilling the desires of the flesh in this way (or in any other way) is self-centered and abusive, even with the other person's consent. 

As pointed out by the Blimey Cow video above, your virginity is more precious than three trillion dollars. So why would you give it to just anyone?