This divorce teaching is tough for us because it speaks directly to our own hardness of heart. The Church has made room for divorce and remarriage "for pastoral reasons;" which is, I think, a very polite way of saying "because it ain't going away."
We talked a little bit about this in lectionary group where one of our number is divorced and remarried. We talked about how hard this scripture is to hear; how it judges, and we determined that it is right for it to judge us because just as the Jews could dismiss a wife because she wasn't living up to her requirements, so too we've made people disposable. The sex isn't good enough. She doesn't cook well. I'm just not that in to her. Aside from reasons of abuse, we are mostly just making excuses for why divorce happens.
And the reason we make excuses, we thought, came in whether a couple was just married or brought together in holy matrimony. That is to say was God at the center of their relationship or not. Living in holy matrimony is a whole lot more work than being married, but the rewards are so very worth it. But often one or the other decides that just being married will suffice. Sometimes a couple that was just married gets set ablaze by the Spirit and finds the joy of holy matrimony. And sometimes couples that are just married stay that way forever.
Still, the odds seem best when one takes heed of the words of Jesus and a) let's God bring people together and then b) works hard not to tear that relationship apart.