The central message of this sermon is that a healthy marriage is not immune to troubles, but rather it's how couples deal with those troubles that matters. The speaker argues that the difference between a healthy and unhealthy marriage is not the presence or absence of troubles, but whether they are able to address and work through their conflicts together. This requires acknowledging that both partners in the marriage are fallen people living in a fallen world, and that their relationships are affected by the pressures and conflicts that come with being human. The speaker emphasizes that blaming one's partner for problems is not an effective way to navigate marriage, but rather couples must take responsibility for their own role in creating and addressing issues. Ultimately, the sermon presents marriage as a "miracle" of two sinners working together in a fallen world, and encourages listeners to approach their marriages with this realistic yet hopeful perspective.