I found out after years of therapy. It was a bit of a shock. My therapist had an idea but kept it to herself for awhile, making vague casual remarks every once in awhile about "parts" to slowly introduce me to the diagnosis. She sent me to her colleague in the same practice (across the hall type deal) who specialized specifically in severe trauma, emdr etc. Who then quietly agreed with her diagnosis and then they talked to my pysch in the same practice and she agreed as well. This was a really long process that involved multiple professionals with different areas of practice, unbeknownst to me, even with the vague occasionally parts comments. Eventually she sat me down one session and we had a long talk about it. I panicked lol. The denial was hardcore. We are extremely covert and it's very hard to tell unless you know me on a very intimate basis (only my therapist, my best friend of 20 yrs and long term partner know and can tell). I think I live pretty much like everyone else without DID, I just have a bit more intense internal commentary. The amnesia is what gets us. But since it's amensia, I don't know what I blacked out on and when. That's where communication with my partner and best friend come in. The more we communicate, we figure out what I've lost. It sucks because I realize how much I miss out on. However, my alters are good people and I know I can trust them when I'm gone, hell we made this far (I'm old btw lol) without people knowing so it's not necessarily concerning, just difficult at times. Denial comes with the diagnosis. It's part of the process. A system is meant to be covert and undetectable. Exposing it is akin to feeling like a life threatening situation. We still won't expose ourselves to even our partner even though we are super safe. He and I have to figure it out with subtle clues (my teen alter is very bubbly and outgoing, so that personality is an indication she was out etc). It takes time.