This also fits in with the "overall context" - 1Cr 7:10 - And unto the married I command, [yet] not I, but the Lord, Let not the wife depart from [her] husband:

1Cr 7:11 But and if she depart, let her remain unmarried, or be reconciled to [her] husband: and let not the husband put away [his] wife.

"the ONLY WAY a Christian is free in a divorce is when the non-Christian leaves the marriage"?? not according to the above verses in the SAME CHAPTER. Notice vs. 11 - "....."let her remain UNMARRIED" which means she became unmarried the moment she left, or deserted and she is to either stay that way or be reconciled to her husband, and the husband is not to put away the wife. There is a big difference in what it says above, and "some others" that read 1Cor7 the way a Roman Catholic would read it, and look down their noses on Christians who have been divorced and remarried as second class Christians.