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 DID.
The whole reason that the DSM has 3 required criteria for DID is because someone can have any 1 of the 3 and not qualify to be DID. So you could have many personalities and not have amnesia and not be in distress or have dysfunction because of it. Then you're not DID, you're just multiple.
If you have 2 of the 3 — again, you're not DID. If you have 2 or more identities and time loss but no dysfunction, then you probably don't need to be diagnosed.
If you have 2 or more identities and no gaps in memory, but you have significant impairment then that's OSDD.
However, note that if you have 2 or more identities, impairment in your life, and don't think you have any gaps in memory — you could be wrong. This is because of how forgetting works in DID — forgetting is very slick. It disappears all the evidence of forgetting. So one could be OSDD and find out later that you are DID after all.
To explain further: 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 traumatized) even while being braced for later revelation of trauma 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.
On the flip side, if there's a Criteria C New which is whether or not these circumstances create significant impairment — then psychology acknowledges that you can potentially be multiple (Criteria A New) and have memory problems (Criteria B New) but without significant impairment — and that would disqualify the DID diagnosis for you. You'd be just as multiple, and just as forgetful — just not dysfunctional or impaired by it.
And if you only have Criteria A New or A & B — you're many people in your system but not forgetting anything and not impaired by it — you'd probably never end up in a diagnostician's office to get a diagnosis in the first place, and just be a self-proclaimed plural/multiple.