This rings so true to me. I got engaged during the last 6 months of my PhD student tenure, and lo and behold, I defended my thesis in the same month we got married. In the same vein as above, the added perspective and fire under me resulted in a number of novel solutions to problems that probably would have been major issues in the past, including a full change in direction of my research conclusions after realizing a substantial issue in the practical application of the technology.

I credit my now wife with the (passive) motivation to shave at least 6-12 months off my time in grad school.