I am a new convert. I have read several of your articles, which have helped in building up my faith.
American marriages are quite different from marriages in my country. Here the bride's parents will give the groom-to-be a list of things to buy or pay that can add up to millions in cash before they will give their daughter to the groom as a wife. There are so many guys who want to do the right thing but unemployment and underemployment are some of the stumbling blocks to getting married in this part of the world.
My question is that if I decide to uphold the scriptural standard, how can a fully matured young man go weeks, months, and years without sexual intercourse?
The problem is not in God's requirements but in the greed of people who have imposed requirements on young couples who strongly desire to get married. There is no biblical requirement for a dowry. The Bible does mention that sometimes dowries were used, but they were not always imposed.
In your country, there are two types of marriages: traditional or customary marriages and legal marriages. Only legal marriages are fully recognized by your government. The traditional marriage is a holdover from pagan days. The traditional marriage allows a man to have multiple wives, which violates God's teachings. Only traditional marriages have a dowry provision. The cost of a marriage license in your country is about half a month's wages. Thus, if your girlfriend is willing to not be treated as a commodity and doesn't care about a traditional wedding, you can get married after the 21-day waiting period.
Regardless, being unable to get married does not give you the right to sin. Sexual intercourse belongs only in marriage (Hebrews 13:4). Until you get married, you have to rely on relieving yourself through wet dreams or masturbation, just as you have been since you were a teenager.
Thank you for your reply and for giving me some useful information about my country's legal marriage. What if the parents of my girlfriend refuse to give their consent if I refuse to pay their traditional rite or only pay it partially? Could my girlfriend and I go ahead and have a legal marriage? Is that kind of marriage valid before God?
Secondly, is masturbation not a sin?
God does not require a particular marriage rite or a dowry. What is required is that marriage vows are exchanged in front of witnesses and that a record of that covenant is kept. See Marriage Covenants. A legal marriage in your country is just as valid of a marriage as a traditional marriage.
If you and your girlfriend are full adults, you don't require her parents' permission to marry. It is polite to ask, but the decision is actually yours alone to make. You and she will have to consider whether you are willing to tolerate the conflict that might arise because you chose not to follow traditions. But again, there is no requirement in the Bible to follow the traditions of men.
Regarding masturbation, see Is masturbation sinful or not?