I'd say that if you need to make silly rules to prevent yourself from cheating on your spouse, odds are that your marriage is already on the rocks... The wedding vows should suffice.
That's cool, whatever works for you. I just personally think that telling your wife that someone was flirting with you, drops a lot of unnecessary anxiety in her lap. I guess it all boils down to trust. I still think that if a married person can't trust themselves around someone of the opposite sex, one must question just how committed they are to their marriage.
I don't mean to pick on you specifically, but I have heard this viewpoint many times before so I hope you don't mind if I quote you in my response.
The common view from those who oppose the "defend your marriage at all costs" camp, is "wow, if you need to do ______ to stay faithful, you must be weak/insecure/untrustworthy/etc"
Does a mighty fortress rely on its walls alone? No. It has additional guards patrolling the area, or additional security such as surveillance cameras to constantly scan the perimeter. Likewise, should we rely on the vows alone, or is it okay to promote practical measures to help ensure that those vows are kept?
Let's remember who the real enemy is here. The true enemy of any marriage is not the tempting co-worker trying to seduce your spouse. The enemy isn't even yourself (for those who state that protecting the marriage means they don't "trust themselves"). The enemy is SATAN. He seeks to destroy anything that brings glory to God. He HATES Christ-centered marriages that are faithful and loving and demonstrate the relationship between Christ and His church. He HATES when people keep their marriage vows. He hates it all because it all exalts and brings praise to the God who designed marriage to be a faithful Union between man and wife.
Satan will use whatever means necessary to destroy a marriage. Some of his methods are blatant, but some are far more subtle and hard to detect. How many men and women in this forum have posted heartbreaking accounts of their marriage falling apart because of something that started so small...as small as a text from a coworker, or lunch alone with a friend of the opposite sex. Every human is born of sinful nature, which gives Satan an awful lot of material to work with. Every marriage has weaknesses, simply because we are human. How could anyone fault someone else for adding additional security precautions to protect something so precious as a marriage?
Logically, it's simple. The more precious and valuable something is, the more security and protection it warrants. Think of the security detail of a local shopping center versus the security of an important government facility. Defending your marriage from does not mean you don't trust yourself. It means you hold your marriage in very high regard.