Including within the non-amorous (I like this better) those who are so "by circumstance" is nonstandard and pretty confusing. A committed monogamous or polyamorous person defines herself as such whether or not she is currently in a relationship. For the sake of consistency, your status as non-amorous should also be independent of whether or not you are currently seeing someone; that is, you should only call yourself non-amorous if you are so by choice.