When I first went to your site, I read through the Growing Up in the Lord: A Study for Teenage Boys and I agreed with what you have said there. However I want to ask if fantasying about your future wife is wrong or not? That and also if reading romance novels about married people was wrong, if it does encourage lustful feelings. I'm still kind of uncertain about what things we can or cannot do and it gives me a headache every time I wonder whether what I am doing is right or wrong in the eyes of the Lord! So I hope you could give me an answer for this matter. Thank you so much.
What often happens is that we confuse the feelings we have for standards of right and wrong. Our feelings might give us hints, but the feelings alone cannot become the standard. For example, is it wrong to have strong sexual desire for a woman? It would be if the woman was someone to whom you are not married, but it would be perfectly suitable for a husband to have such desires for his wife.
"Drink water from your own cistern, and running water from your own well. Should your fountains be dispersed abroad, streams of water in the streets? Let them be only your own, and not for strangers with you. Let your fountain be blessed, and rejoice with the wife of your youth. As a loving deer and a graceful doe, let her breasts satisfy you at all times; and always be enraptured with her love. For why should you, my son, be enraptured by an immoral woman, and be embraced in the arms of a seductress?" (Proverbs 5:15-20).
Thus it is not the feeling that determines whether something is right or wrong but whether acting on that feeling is going to lead you to do something that is right or wrong.
"What comes out of a man, that defiles a man. For from within, out of the heart of men, proceed evil thoughts, adulteries, fornications, murders, thefts, covetousness, wickedness, deceit, lewdness, an evil eye, blasphemy, pride, foolishness. All these evil things come from within and defile a man" (Mark 7:20-23).
When you examine something for appropriateness, you need to look see if what is being imagined or done is proper according to God's teachings. Therefore, imagining what life will be like with your future wife would be fine, so long as you realize that imagination and reality don't always match up. It is possible to build such high expectations that you find yourself disappointed when faced with reality. The book Song of Solomon is a description of love told from the woman's point of view. During her courtship she constantly imagines what her married life would be like.
"He brought me to the banqueting house, and his banner over me was love. Sustain me with cakes of raisins, refresh me with apples, for I am lovesick. His left hand is under my head, and his right hand embraces me. I charge you, O daughters of Jerusalem, by the gazelles or by the does of the field, do not stir up nor awaken love until it pleases" (Song of Solomon 2:4-7).
When her thought became too intimate and started dwelling on sex, she would stop herself. She understood that focusing on such things would rush the relationship in an unhealthy way. If nothing else, it would increase the temptation to have sex before marriage. Love needs to develop at its own pace. It can be easily damaged if it is rushed.
Romance novels lead to a different problem. It encourages the ideal of voyeurism. Just as it would not be right to peek through the window to watch a married couple have sex, it is not healthy for you to read and think about the sexual relation another couple might be having explained to you in detail. The fact that married couples have sex is to be expected. But it is a different matter to read intimate details of their sexual actions. Such, as you noted, are only being give to stir up strong sexual feelings in you.
I hope this clarifies the boundaries better for you.