I agree with Xeneon in most comments, but if you are one to feel trust easily, there is a possibility you may tell about it at the wrong time, too soon.

Honestly, I wouldn't say anything about it until there is a need or they start asking questions about what they see or experience with you.

I didn't say anything to my partner and one day I crashed, I was blessed because he helped me through it. I was very lucky that his sister and mother both suffer with depression so he understood the theory...crash...get help...get better... crash...get help...get better...through the cycle as it goes. He's even used to my alters now because he always thought (as I did) that I was just speaking in another voice to be humerous, or in the child megs voice to be cute (meg comes out when I can't talk for myself, she gives very gentle hints that are usually not gotten). So he copes with that know as easy as pie.

Good luck with it kimby,
Love & Blessings,
Rhian