...it might be that he has a good reason for you not to know. Perhaps he thinks it is unsafe and wishes for you to not be targeted?

[But he knows from experience that hiding the truth seldom works out as planned. Isaac had met Sitri without William even knowing it and summoned yet another demon. And Mycroft Swallow's father had used a body suit by a monster.

Reality cared little for what one wanted to share sometimes.]

I know you wish to respect his privacy, but perhaps it wouldn't hurt to confront him about it directly. Or at least to tell him you will support him.