Since the Nicolaitans are mentioned prophetically as if it is assumed the reader knew who they were, what we need to interpret the Nicolaitans should be found in scriptures already recorded. The word on its face implies the meaning "followers of Nicolas." Conveniently, there is a Nicolas recorded in the Acts of the Apostles (and no where else), who was an early Greek (rather than Jewish by birth) deacon of the church in Jerusalem. There is no dearth of ancient extra-biblical sources who report that he went astray, particularly in matters of sex, in his latter years (although there is at least one credible source that says that wasn't the case).
In light of these musings, I find it interesting that the Holy Spirit found it necessary to repeat warnings in the scriptures about men not having their own wives with whom they were sexually active. The teaching that forbade marriage is, in fact, classified as a doctrine of demons. Christian men generally disavowing and denying themselves sexual relations (within the context of heterosexual marriage) could only lead to trouble. For those who attempted to practice unnecessary, unspiritual restriction on God-designed activity, something was bound to break.
Although historical accounts of Nicolas are somewhat fuzzy, there does seem to be agreement amongst them that he endeavored to abstain from sexual relations with his wife. At some point something did break, and the rebound effect was those following his teaching embraced license rather than restraint. Nicolas went beyond Paul's teaching to beat the body into submission to abusing the flesh in order to overcome it. One never need to practice evil in order to achieve good, and certainly should never engage in sexual immorality in the name of mastering the desire for sex.
Balaam in the OT was of a similar ilk--what he could not get from God directly (the cursing of the Israelites), he sought to get by enticing the Israelites to sexual immorality and idolatry. Any teaching that espouses sexual or moral license as a means of attaining something spiritual, even something like self-control, is a Nicolaitan or Balaamite doctrine. Spiritual benefit never comes through the auspices of fleshly excess. Overcomers know this and avoid the Nicolaitans and their works of the night.