Noach was a Tzadik Tamim
When the Torah tells us about the prohibitions of seeking answers about the future through sorcery, it says in the Pasuk, "תמים תהיה עם ה' אלוקיך - You should have a perfect (faith) with Hashem your G-d." The Torah is teaching us not to worry about the future and instead trust in Hashem with a 'perfect' faith, that He is taking care of us and knows what He is doing. When we seek answers about the future on our own, it shows that we are trying to take control of our own destiny and are not trusting enough in Hashem.
The word "Tamim" is also used in reference to Shmiras Habris. Noach was called a Tzadik Tamim. Chazal say that Tamim refers to the fact that he was "גדור מן העריות - guarded from promiscuity". Also, when Hashem introduced the mitzva of Bris Mila to Avraham Avinu he prefaced it with the words "התהלך לפני והיה תמים." So how does the word "Tamim" (which implies a perfect faith) tie in with Shmiras Habris?
Perhaps we can explain it as follows. When a person looks at other women or pursues forbidden pleasures, what he is really feeling deep down is that Hashem doesn't provide him with all he needs and he, therefore, takes his needs into his own hands, either by looking at that which isn't his or by indulging in pleasures that weren't given to him by Hashem. In order for us to be Shomer Habris, we must let go of control and develop a "perfect faith" that Hashem is providing all our needs. The pleasures that we sometimes feel we need so much, we DON'T really need. If they were true needs, Hashem would have given them to us - or permitted them to us.
Yes, we CAN let them go. Hashem is taking perfect care of us. He doesn't need our help at all. And, indeed, we find that the more a person tries to take his needs into his own hands, he starts to LOSE that which Hashem had previously provided him. Many people report losses in Parnassa, Nachas, Shalom Bayis, Inner Peace, and so many other important things. This is a direct message from Hashem - מדה כנגד מדה- that if we think we take our needs into our own hands, Hashem will show us which needs are REALLY important, and WHO is it that was really providing our needs all this time.
The more we let go of our "perceived needs" and TRUST in Hashem to care for us, the more we allow the light of Hashem to flow through us and bring true blessing into our lives.
Developing a "perfect faith" is not an overnight event, but we need to constantly grow in that direction... תמים תהיה עם ה' אלוקיך is so important in the life of a Yid, and it is the underlying secret to Shmiras Habris.