Married life can be hard. It can be hard for 21st century Americans, and it could be hard for 1st century Judeans. If it weren’t, the Pharisees wouldn’t have pressed Jesus on the subject of divorce, as they did in today’s gospel. In response, Jesus explained that marriage was intended by God to be permanent. Yet to some then and to some now, this seems to be an unreasonable standard, because marriage can indeed be so hard.
Jesus spoke of husband and wife becoming one flesh. This refers to much more than a physical union. Instead, it’s a call to an intimate union of two persons which requires personal change, self-sacrifice, honest communication, openness to new life, and a desire to meet one another’s needs, heal each other’s hurts, and help one’s spouse become the person God intended him or her to be.
To do this is hard, and God knows it. He knows our selfishness, our neediness, and our fear of conflict. And God knows that it’s tempting for us to run away from problems instead of facing them head on, and to imagine that the grass is always greener on the other side of the fence.
This is precisely why God designed marriage in the way he did. Because it takes a permanent commitment in order for marriage to flourish and grow, instead of it being crushed by our "hardness of heart."