THank you, every one of you, for your replies - it's really given me a lot to think about. I think the first course of action will be to discuss as you've recommended, re: whether he understands DID and precisely where he currently stands. I think I'll probably ask my partner in to the session to provide some support and strength; it's difficult to talk about some aspects without her to help ground, I get easily overwhelmed.
Also, thank you guys for calming me down enough to approach this sensibly rather than through blind panic
