A Confusing Passage?

Q.  A lady friend tells me she couldn’t marry me unless her current husband becomes unfaithful leading to a divorce.  She quotes 1 Cor. 7 and says she would have to remain single if she divorces because of extreme unhappiness.  I’ve read the passage several times, and, like most of the Bible’s verses, I am confused.  What is the best way for me to gain understanding of 1 Cor. 7? By the way, this is hypothetical, part of a Bible study.  I’m not romantically involved with her.

A.  1 Corinthians 7:10-11 says,

“To the married I give this command (not I, but the Lord): A wife must not separate from her husband.  But if she does, she must remain unmarried or else be reconciled to her husband. And a husband must not divorce his wife.”

I don’t see anything confusing about it.  Jesus taught that the only acceptable reason for divorce is marital unfaithfulness (Matt. 19:9).  If your friend leaves her husband for any other reason, the Bible says she is supposed to remain single.  Marrying someone else would be a sin.