The answer
Simply through effective dialogue which edifies. They must be convinced by themselves that pre-marital sex results in many harmful things, not the least being sex addiction. They must be convinced that these relationships are not the correct way to prepare themselves for marriage, or assist them in choosing the right partner, for such relationships are body to body relations only, whereas marriage is a person to person relationship. Entering the door of marriage through adultery will result in divorce and broken marriages. Therefore, the young people must understand that marriage is a commitment; it is not something sensual only, and that the sensual aspect is only a small component of marriage. In a Christian marriage, there is love and intellectual co-operation, and spiritual co-operation to build each other for the purpose of entering the Kingdom of Heaven. Therefore, rather than imposing our thoughts on them, they must be personal convinced that such relations are wrong.
H.G. Bishop Moussa