story identification - Looking for a book with parallel universes like pages, possibly with "maze" in title, and a black Jewish female character

Looking for a book. A series, actually. The main characters were a Jewish man and a black woman who was his wife. There was a running gag when she would tell people her last name and they thought it was unusual that a black woman would have a Jewish name.

They went on adventures in parallel dimensions. I believe that each book had a word repeated in the title, maybe "mirror?" Or "maze?" Or "page..." it seems they jumped into worlds through a tool like a mirror or a book.

The parallel universes were like pages, and the pages closest to you were most similar but the further you got the further they were from your life. One page over might be that you had something different for breakfast and so now you have a tummy ache, a few more pages over you might have become a prostitute, too far and it was theorized that humans had evolved differently altogether, I didn't get that far in the series. For adults, and humorous.

I read them about 15 years ago, so they are not new. I would love to find them again.

Answer

These are the G.O.D Inc books by Jack L. Chalker.

The woman's name IIRC was Horowitz

The black Jewish woman, I think, is a fairly unique marker.

In the first book they are introduced to the "labyrinth"; in the second book the woman travels to a world where she had become a prostitute instead of a private eye and a virus from a world line where the dominant species not being entirely human was a plot point.