I have a question for you. I'm trying to stop lusting for people in the streets, etc. but do I also have to give up the lust that I have towards my wife?
(Note: although Boruch's answer below is a bit long, it is well worth your while to carefully read and even re-read the quotes that Boruch brings below from the White-Book of SA. If you are married, it can change your entire perspective and give you a much deeper understanding of what exactly it is that we are trying to "break free" of. If you don't have time to read it now, perhaps print it out to read later).
You're right on target. Natural desire is fine, but lust, even in marriage, is a serious problem for the lust addict and can be fatal.
What is the difference between natural sexual desire and the sexual desire that we (in SA) call lust?
The natural desire for sex is a desire to encourage us to have children, to encourage us to naturally give love to our wives, rather than taking love from our wives, and to enhance our relationships with our wives and bring us closer together. That is not what we call "lust" in SA. However, that very same desire for sex with one's wife used selfishly and self-centeredly to make ourselves feel better and to "drug" on, is most certainly a problem.
"Creation gave us instincts for a purpose. Without them we wouldn't be complete human beings. If men and women didn't exert themselves to be secure in their persons, made no effort to harvest food or construct shelter, there wouldn't be any survival. If they didn't reproduce the earth wouldn't be populated. If there were no social instinct, if man cared nothing for the society of one another, there would be no society, So these desires for the sex relation, for material and emotional security, and for companionship are perfectly necessary and right, and surely God-given.
Yet these instincts, so necessary for our existence, often far exceed their proper functions. Powerfully, blindly, many times subtly, they drive us, dominate us, and insist upon ruling our lives. Our desires for sex, for material and emotional security, and for an important place in society often tyrannize us. When thus out of joint, man's natural desires cause him great trouble, practically all the trouble there is. No human being, however good, is exempt from these troubles. Nearly every serious emotional problem can be seen as a case of misdirected instinct. When that happens, our great natural assets, the instincts, have turned into physical and mental liabilities."
"... sex is a natural function... The real problem of this addiction seems to be what we call lust - an attitude demanding that a natural instinct serve unnatural desires. When we try to use sex to reduce isolation, loneliness, insecurity, fear, tension, or to cover our emotions, make us feel alive, help us escape, or satisfy our God-hunger, we create an unnatural appetite that misuses and abuses the natural instinct. It is not only more intense than the natural but becomes something totally different... sex enters a different dimension; ... it takes on an unnatural spiritual component."
"What Is Lust? ... A Personal Point of View...
Lust is not sex, and it is not physical. It seems to be a screen of self-indulgent fantasy separating me from reality - either the reality of my own person (in sex with myself) or the reality of my spouse. It works the same way whether with a girlfriend, a prostitute, or my wife. It thus negates identity, either mine or the other person's, and is anti-real, working against my own reality, working against me.
I can't have true union with my wife while lust is active because she as a person really doesn't matter; she's even in the way; she's merely the sexual instrument... With lust, the sex act is not the result of personal union; sex doesn't flow from that union. Sex energized by lust makes true union impossible...
... Seen in this light, lust can exist apart from sex. Indeed, there are those who say they are obsessed with lust who can no longer have sex. In my experience, lust is not physical; it is not even strong sexual desire. It seems to be a spiritual force that distorts my instincts; and whenever let loose in one area, seems to want to infect other areas as well...
Therefore, my basic problem as a recovering sexaholic is to live free from my lust. When I entertain it in any form, sooner or later it tries to express itself in every form. And lust becomes the indicator of not only what I do, but what I am.
But there is great hope here. By surrendering lust and its acting out each time I'm tempted by it, and then experiencing God's life-giving deliverance from its power, recovery and healing are taking place, and wholeness is being restored - true union within myself first, then with others and the Source of my life.