...typically, offenses with a sexual component, although criminal violations under the UCMJ, will typically fall outside the investigative purview of MP/CID unless there is an aggravating circumstance such as violence (i.e., rape, forcible sodomy) or material consideration (i.e. prostitution, sex for drugs, etc.) Normally, the adultery and fraternization-type issues are the stuff of commander's inquiries, IG, EO or congressional complaints and are examined by an investigating officer appointed from within the unit under AR 15-6.
Specifically, with regards to Article 133Conduct unbecoming an officer and gentleman, the accused must be:
"Any commissioned officer, cadet, or midshipman who is convicted of conduct unbecoming an officer and a gentleman shall be punished as a court-martial may direct."
Not only are NCOs exempted from this, so are warrant officers (at least I would think, WO1s, as in recent years, Warrant officers generally also receive commissions at the CW2 level).
All uniformed service members, regardless of appointment, rank, etc. are subject to the, "catch all," Article, Article 134 which specifies some specific acts but also criminalizes any activity wherein:
(1) That the accused did or failed to do certain acts; and
(2) That, under the circumstances, the accuseds conduct was to the prejudice of good order and discipline in the armed forces or was of a nature to bring discredit upon the armed forces.
Adultery is always serious, but you wonder if something happens during a war, if the guy or gal would be tossed out.