Here's a common occurrence chez moi:
In the loo I'm currently reading 1001 Books You Must Read Before You Die. I started reading it 2014 and expect to finish it in 2017. After than I'll probably read 1.000 Places You must See Before You Die.
I usually keep books of articles and essays in the kitchen that I grab to get my reading fix with my breakfast whenever I haven't brought in another book that I'm carrying around between rooms. Currently, however, I'm reading The Boy's Book of Survival (How to Survive Anything, Anywhere).
I might be reading a novel and a travelogue by turns in the bedroom and living room. In addition I always have a book or two loaded into my smartphone for reading in the queue at those unhappy times when I have to go shopping for food during rush hour.
That makes five active reads, but I have had as many as ten books on the go at once, and back in college I sometimes juggled that number of school books in addition to one or two leisure reads. If you were to count all the books strewn around my apartment with bookmarks sticking out of them you might think I have as many as thirty books on the go, but I only count books I have read something in at least once in the past week, whereas some of the bookmarked books have lain untouched for a year or more. I guess this makes me a promiscuous reader.
I seldom get confused, and that is only on the rare occasion when I accidentally start reading two very similar books, for example with a similar story background or lead characters with the same or similar names. The trick, if there is one, is to never read two books of the same genre or by the same author at the same time.
Mind you, I don‘t do this all the time. I might have, say, four books going, but if one of them suddenly becomes too absorbing to put down, I will put the others aside and concentrate on that one book to the end. I might also go through periods when I only read monogamously for weeks or months on end, but I eventually will move back into the wondrous polygamy of book-hopping.
The advantage of book-hopping over reading one at a time is variety. I could be simultaneously enjoying a travelogue from Africa, reading a novel and learning about Japanese cuisine, but the downside is that it can interfere with continuity and make it difficult to become really absorbed in a book.
So, dear reader: Are you a promiscuous or a monogamous reader, or somewhere in-between?