The Bible condemns the act of intimacy before marriage while encouraging abstinence. It is important to understand that there is a significant degree of mutual dependence between these two terms. The Bible is very clear that there should be no sexual relations before marriage. There are no exceptions anywhere in the Bible, and therefore, even if a man and a woman are engaged to be married, it is a sin for them to have premarital sex.
The Bible gives no subsidy nor is there any tolerance for any sex at any time before your marriage. If he does not, the wrath of God will fall on both of them and no one will be exempt from guilt if there is sexual intercourse before a couple is legally united before God in a legal marriage. That is God's intention and it is one of the most serious sins that exist when even a committed partner has sexual relations before marriage. Perhaps the best book in the Bible about the joys of sex is the Song of Songs, as it reminds us that sex is strictly for marriage.
Simply having sex or living together does not fulfill the functions of the biblical model of marriage. In due time, it will give itself to you in a more complete, beautiful and complete way because you have appreciated it enough not to use it in a sinful and unbiblical way.