[Raziel]

Soul mates were never regarded as multiple partners:

Via dictionary. Com

"Though the phrase soul mate gained steam toward the end of the twentieth century, the idea goes all the way back to Plato’s Symposium, written in 385–380 BCE.
In Symposium, when the two dialogists discuss love, Aristophanes tells Socrates that human beings used to have four arms, four legs, and two faces, and they were happy and complete. But Zeus was jealous and split them in two with his thunderbolt, and now humans spend their lives searching for their other half. This idea of an “other half” has been with us ever since.

But the phrase soul mate itself was first recorded in 1822, when the poet Samuel Taylor Coleridge wrote in a letter, “To be happy in Married Life . . . you must have a Soul-mate.”

It's the new age type authors redefining terms to suit book sales.

Lots of well meaning people are being openly deceived & what's worse is that they try to convince others.