The Latin Parish Cana of Galilee: A Witness to the Words of Christ on Marriage

It could not be any more clear.  Unfaithfulness justifies separation from bed and board, but the bond of marriage remains unbroken. 

Jesus said in the Bible:

"It was said, moreover, 'Whoever puts away his wife, let him give her a written notice of dismissal.'  But I say to you that everyone who puts away his wife, save on account of immorality, causes her to commit adultery; and he who marries a woman who has been put away commits adultery."

-St. Matthew 5:31-32