It means what God has made can not be broken. If you were married in his church at his alter the spiritual bond between you two can never be broken. She will always be your wife. I don't think they litteral mean flesh either. It is a soul bonding.
This is generally a Catholic teaching of those versus. But I think it still applies to all faiths. Notice on the later versus it follows the Marcan source. In the beginning there was no divorce, but Moses allowed it because of the hardness of your hearts.
This soul bonding with my wife is the reason I'm here. I know I love her, and nothing is going to change that. Mine is just a little lost right now. I tend to think she went to Iraq or something, and can't get home right now.
