He already has a work account and a yahoo account. I discovered this 3rd account by accident, when checking history. It makes sense he might choose a German provider if he were trying to keep something from me. It's a language he knows well and I don't know at all. . . very sneaky!
There must be an explanation other than the one I'm thinking of. Right? (I couldn't guess the login name & password, btw.) What to do now?