In the years leading up to the "I'm not in love" statement from my wife, I was the die hard husband. I worked incredibly hard trying not to have any excuse for to be called a poor husband. However all my efforts did not seem to make my wife happy (enough). She tend to have a ambivalent attitude toward our marriage. Even though we would go out and do things together, this did not seem to improve our relationship. Finally when I pushed her hard enough one night about our relationship she finally came with the "not in love with you any more" statement.
Since I found DB and have studied most of it, it has become quite clear that she felt love was an in or out thing/ feeling, and not a work in progress. She felt it was all her problem and didn't want to hurt or bother me with it. She worried that I would take it very personal, and that would only make things worse. Perhaps that would have been true, I think I would rather have dealt with things a little earlier in the game.
Although things have changed and I have made a lot of big 180s, we are only now starting to feel comfortable with each other again. My feeling is that love is a work in progress and not a uncontrolled state of mind. Although the later makes those of us who want to put little effort into it feel good (not our fault), a loving relationship becomes what you put into it. Although my wife and I were doing the external stuff to build a relationship, we were not taking care of the interpersonal stuff (expressing inner feelings about how we truly felt). Needless to say the problem just piled up till something had to be said.
I know hind site is 20/20 but all I would say to new couples these days is work on your relationship and realize that love is not just an uncontrolable phenomenon, but a day by day work in progress. The sooner my W and I learn this lesson and apply the new principles, the sooner we'll be back on track. Since a marriage is a team effort, we'll both have to apply this lesson.