The first part of Chumash B'midbar speaks of events directly related to the Hashra'as Hash'china -- the dwelling of the Divine presence -- in the Mishkan. The counting of the L'viyim (Levites), which began in last week's portion and finished in our parsha, was designed to enumerate those working in the Mishkan. Similarly, the count of the rest of the tribes was, amongst other reasons, to facilitate Hashra'as Hash'china, since Hashem's presence would only rest on K'lal Yisrael after they had proved their lineage and divided themselves into sh'vatim (tribes). Our parsha also includes the rules of sending the various t'maim -- ritually impure individuals -- outside the camps just created: the Mishkan in the center, surrounded by the camp of the l'viyim and then the camp of the rest of the sh'vatim. Our parsha ends with a description of the specific, dedicatory offerings brought by the n'si'im. All of these elements revolve around the Mishkan. Surprising it is then that the Torah seems to interrupt these connected portions with the commandments concerning the Sotah (adulterous woman) and the Nazir.
Perhaps we can suggest a resolution based on a well-known answer to a difficulty in the entire last section our parsha. All of the n'si'im offered exactly the same korbanos; yet, the Torah carefully describes each prince's offerings in detail. Many explain that this repetition teaches us a fundamental principal in Judaism. Although we are all bound by the same 613 mitzvos and are prohibited from seeking out other forms of Divine service -- which only lead to disastrous results as in the case of Nadav and Avihu, the episode of the Golden Calf, Korach's rebellion and others -- each member of K'lal Yisrael brings his unique personality with him in his performance of the mitzvos. The Midrash Rabba elaborates that although each nasi brought the same korbanos, the intended symbolism was different in each case. Similarly, all learn the same Torah; yet, we have our great Poskim, outstanding Torah lecturers, learners of Daf Yomi, those who excel in the study of aggada and hashkafa, and those who learn basic halacha. Rav Z. H. Chajes zt"l even notes that there were two academies in the time of the Talmud: one for Aggada and one for Halacha. This is why, he notes, that certain amora'im (Talmudic sages) are rarely quoted in matters of Halacha but are abundantly quoted in areas of Aggada. Similarly, concerning mitzvos, our tradition allows for varying amounts of time spent on one mitzva at the expense of another and vice-versa depending on the individual, all within the system of Halacha. Already in the times of the Talmud, amorai'm had different approaches to the proper balance of time devoted to prayer versus study (see Shabbos 10a). A prominent, contemporary Rav once noted that these diverse postitions seem to have carried over to some extent in the different approaches of the Lithuanian Yeshiva world and their disciples as opposed to the Chassidic world.
Rabbi Menachem M. Schneerson zt"l, the late Lubavitcher Rebbe, noted that this dialectic of diversity within sameness is indicated by the two prime celestial bodies which govern the structure of the Jewish calendar. Whereas the months are lunar, the year is solar (hence the need for "leap months" to keep the calendar synchronized with the solar seasons). The moon constantly changes; the sun is constant. The mission of the Jew is to merge both qualities: within the solar-like sameness of the mitzvos, to carve out his unique lunar-like niche.
Partaking of the physical pleasures of the world within moderation for the purpose of nurturing the body and providing the necessary physical happiness to serve as the backdrop for 'avodas Hashem is the approach the Torah advocates for most. Indeed, R. Elazar HaKapar teaches us that the Nazir is referred to as having sinned because he abstained from wine (see Rashi 6:11). But yet, the Nazir is referred to as a "Kadosh" (holy one) (6:8)! The resolution seems to be found in Rashi's comment (6:2) from the Talmud explaining the juxtaposition of the parsha of Sotah with that of Nazir. One who sees the humiliation of a sotah in the Mikdash should become a nazir. This statement seems to be teaching us that one who discovers that he is prone to misuse physicality for the wrong ends, leading to immorality should separate temporarily from some of the generally permissible pleasures of the world until his attitude can be modified. This is similar to the approach the Rambam outlines in Hilchos Dei'os for one who finds himself weak in a particular characteristic. His cure is to temporarily adopt the other extreme of the quality in question. The Kli Yakar notes that the passuk that criticizes the nazir for "sinning" is in the context of one who became tamei in the middle of the nazirite period and must restart it. Therefore his abstention was in vain. A nazir who utilizes his period of rest from 'olam hazeh for a spiritual goal is called a kadosh. Here too, we find diversity within the basic structure of the Torah. Perhaps this is why the Torah places this parsha before that of the n'si'im.
The natural desire to be unique should never be used to distance oneself from normative, Halachic practice. Rather, it must be channeled to find one's unique role within the inherent diversity present within the same 613 mitzvos.