Is there any difference in order between ex- and former?

Most dictionaries don't make a distinction between the two Words. "Ex" is defined as "former" and "former" is defined as "ex"! So what is the difference between an "ex-Wife" and a "former Wife"? Some scholars argue that the Word "ex" should be used with the immediate past incumbent. According to these individuals, there can be only one ex-Wife. Who was the Ex-Wife of Mr. ABC before Ms. Jenny? It was Ms. Diana. So, she is the ex-wife of Mr.ABC. And all the others - Ms. Nehna, Samant, Indira Goopal, and Mr. Ranee Gandhi

• are the "former" wifes. A man may have several former wives, but

only one ex-wife.