I found some of your insights on the subject of masturbation quite amazing. As an evangelical, we are taught to develop spiritual disciplines of which self-control is one. In fact, in Galatians 5:22 the apostle Paul highlights it as one of the fruits of the Spirit. To this effect, it is argued that, if one is separated from their spouse for a prolonged period of time, masturbation would be wrong as it would imply that one is not exercising self-control and as such not being fruitful (II Peter 1:5-8). As such it is advised that one endure the separation until he reunites with his wife, as masturbation would, in any case, amount to cheating on his wife and thus defiling the marriage bed (Hebrews 13:4).
Could you please address these difficult questions in doctrine and theology?
Does one exercise self-control over his appetite by refusing to eat or by controlling the amount he eats? Does a person exercise self-control over his thirst by never drinking or by limiting what he drinks to things that are good for him and does not affect his sobriety? When it comes to physical desires, self-control is manifested in controlling when those desires are satisfied, so that sin does not occur.
One controls his appetite for food by eating regular amounts so that hunger does not cause him to lose control. A person controls his thirst by staying well-hydrated so that thirst doesn't drive him to quench it with alcohol.
It is no different with the desire for sex. In marriage it is satisfied with regular sex between a husband and wife. "The husband must fulfill his duty to his wife, and likewise also the wife to her husband. The wife does not have authority over her own body, but the husband does; and likewise also the husband does not have authority over his own body, but the wife does" (I Corinthians 7:3-4). An absence of sex causes temptation, which might lead to a lack of self-control. "Stop depriving one another, except by agreement for a time, so that you may devote yourselves to prayer, and come together again so that Satan will not tempt you because of your lack of self-control" (I Corinthians 7:5). Thus, it should be argued that prolong separations are to be avoided, so that self-control can be maintained.
For males the desire for sex is tied their production of semen in the seminal vesicles. The glands producing semen have limited storage capacity and ejaculation is required when the limits are reached. As the glands fill, the desire for sex rises. The production of semen in a healthy male is continual, so to argue that a man ejaculating because he ran out of room to store semen and doesn't have access to his wife is somehow cheating on her is false because he will still be able to have sex when he reunites with her. The semen he ejaculates will be replaced.
The use of Hebrews 13:4 contains a false comparison. "Marriage is to be held in honor among all, and the marriage bed is to be undefiled; for fornicators and adulterers God will judge" (Hebrews 13:4). Sex within marriage is undefiled. Fornication (sex outside of marriage) and adultery (sex where at least one person is married, but not to the person he is having sex with) are a defilement of God's laws and the people involved in it. This verse isn't saying that fornication and adultery are defiling marriage. You could argue that adultery defiles a marriage, but in the case of fornication, there is no marriage to be defiled. This verse is more closely tied to the same idea Paul expressed, "Flee immorality. Every other sin that a man commits is outside the body, but the immoral man sins against his own body. Or do you not know that your body is a temple of the Holy Spirit who is in you, whom you have from God, and that you are not your own? For you have been bought with a price: therefore glorify God in your body" (I Corinthians 6:18-20). There is nothing wrong with sex within marriage, but sex outside of marriage makes the people involved unholy. "As obedient children, do not be conformed to the former lusts which were yours in your ignorance, but like the Holy One who called you, be holy yourselves also in all your behavior" (I Peter 1:14-15).
However, there is an assumption that somehow masturbation is either fornication or adultery, but it doesn't fall under either category. Both fornication and adultery are sexual acts involving other people, but masturbation is done alone. Both fornication and adultery clearly break God's law, but masturbation (by itself) is never listed as a sin; instead, it is listed as unclean (Leviticus 15:16-17), just as sex (Leviticus 15:18) and a woman's menstrual period (Leviticus 15:19-23) are categorized as unclean. Notice especially Leviticus 15:18 and realize that sex between a husband and wife is both unclean and undefiled. Sex within a marriage is not a sin, and neither is ejaculating or having a menstrual period. Sex can be used sinfully when it is done outside of marriage and, thus, break God's law. Masturbating can be used sinfully when the person is involved in pornography (I Thessalonians 4:3-5), lust (Matthew 5:28), or involved in mutual masturbation because these break God's law.
When a man ejaculates through a wet dream or by masturbation without lust, those ejaculations reduce his desire for sex and aids him in maintaining his self-control. It is the man who tries to deny himself all ejaculations who is in the greatest danger of losing self-control.