Not from Abuse
There are people who are absolutely certain they are multiple and have not been abused or not sufficiently had any trauma to account for the psychological model of abuse-generated DID.
Anything is possible. Even DID without an abuse cause.
But this presents a big conundrum with regard to forgetting and abuse, and one's certainty and whether that certainty is permanent for the rest of this lifetime.
Due to the nature of strong dissociation and hiding memories from oneself, which is a criteria of DID, it's always possible a multiple is certain they have not experienced abuse or trauma and later finds out they did. This puts support persons and resources like this one in the awkward position of having to validate an individual's authentic subjective experience (of never having been abused) even while being braced for later revelation of abuse that has previously gone missing. All multiples are different and this later revelation is always a possibility, so be warned that your current lack of evidence can change due to the nature of the disorder.
It's a chicken & egg dilemma or a catch-22. It's impossible to be certain that you definitely have never been abused if you meet Criteria B New of the DSM-V criteria for DID. Check out the article on Criteria B for the various types of forgetting that occur in DID.