Is it true that if you divorce your first husband that you are not to remarry him?

Actually it is ok according to the Bible, at least assuming that neither have gotten married to anyone else in the meantime.

1 Corinthians 7:10-11 And unto the married I command, yet not I, but the Lord, Let not the wife depart from her husband: But and if she depart, let her remain unmarried, or be reconciled to her husband: and let not the husband put away his wife.