So to summarize: lots of dates→a few casual relationships (<1 year)→1-3 serious relationships (Avg: 2 years for each failed relationship, 3 for the one that reaches engagement)→engagement (Avg: 1 year)→marriage.
So, ignoring casual dating and relationships that end fairly quickly, the average person who has 2 serious relationships that don't work out before finding their spouse will spend 4 years in dead end serious relationships, 3 years dating their future spouse, and another year in an engagement period before getting married. For a grand total of 8 years in serious, romantic relationships and 4 years in a relationship with their future spouse.
Now, not everyone approves of this method of reaching marriage. In Christian circles there is a courtship movement. These guys heavily emphasize the roll of the father in the courting process and also generally do not allow private 1 on 1 interaction unless in a controlled environment. They also put some pressure on both the man and the woman to decide whether they were willing to commit to each other. If after just a few months they didn't want to get married, the courtship was broken off.
Courtship does not have a good reputation and is generally thought of as outdated. Indeed, courtship was designed in and for another time period and I don't think it is the best way to go about seeking marriage. However, there are things we can learn from the courtship model, specifically the disdain for casual romantic relationships.
If they cannot exercise self-control, they should marry. For it is better to marry than to burn with passion. (1 Cor. 7:9 ESV)
Flee from sexual immorality. (1 Cor. 6:18a ESV)
The BF/GF relationship is not biblical. Try as you might, there are simply no examples of such a situation in the Bible. However, that does not necessarily mean it is unbiblical, but at the very least, it is extra-biblical, and we should take that in to account when evaluating it.
Now a BF/GF is by definition a companion with whom one has a romantic (or, in a more overt defiance of Biblical teaching, sexual) relationship. The huge problem with this is that romance is just sexual emotion; it is always meant to lead to intimacy between a man and his wife. The difference between romantic love and brotherly love is that one is sexual and the other is not. Even where a romantic love is portrayed between 2 unmarried people in Song of Solomon, what is the result of said romance? A passionate longing to be married and consummate their relationship. Romance was never meant to be divorced from physical sex. They were always intended to go hand in hand.
The problem with the modern concept of the BF/GF relationship is that it has romance without the sex. It has sexual emotion without the physical sexual fulfillment and release of that emotion. The modern BF/GF is a relationship that is constantly getting deeper and more intimate between two people who are also physically attracted to each other (else, why would they be dating?). As such, the couple should get closer to marriage as their relationship gets deeper and more intimate. Marriage should be the goal. They should marry before they are so close to one another, so intimate, so in love, that they are in danger of following that desire into fornication.
Unfortunately, in our culture the BF/GF relationship is not treated as a transitory state where they are pursuing and considering marriage and, once they've made a decision, they either get married or break it off before they become extremely close. (Side note: a whole other huge problem with the modern BF/GF relationship is that breakups effect the couple in the same devastating ways a divorce does.) Rather, the BF/GF relationship is considered to be a completely legitimate relationship state for years on end, with only the most barely perceptible advance towards marriage. People often begin dating in high school while not intending to marry until after graduating college. That's a minimum of 5 years where they will be searching for/in a committed romantic relationship without even the possibility of marriage.
Is it any wonder that so many Christian couples today are struggling with remaining chaste until marriage? According to a CNN article, approximately 80% of self-identifying evangelicals do not wait until marriage. Now, that is "self-identifying evangelicals," so there is probably a significant percentage of Christians-In-Name-Only here, but even taking that into account, there is still a huge percentage of Christians who have fallen into sexual sin at least once. There are many committed Christians who planned on waiting until marriage but finally fell into sin after resisting months or even years of ever increasing ungratified sexual desire. It is incredibly difficult to resist this temptation in the moment, that's why Paul said to flee from sexual immorality, not stand and fight it, and certainly not court it from a distance in the form of an emotional affair with a BF/GF where the emotional intimacy has long since past the point where sex is the natural result.
So what is the Christian man who desires marriage or "burns with passion" to do? The answer is simpler than you think: get married. There's no need to follow all the rules of the old-fashioned courtship method, rather, as you begin dating a girl, frame the relationship around the idea that you are pursuing and considering marriage, and if, after a few months to a year, you don't want to marry her, cut her loose and try again.
