Seems to me too many people have unrealistic expectations about the other individual. One of the biggest challenges in a relationship is to learn to expect the unexpected and to adapt to growth and change in one another. People often complain that their partner "changed." Well, gees, we're all going to change in some way or we're not growing. Relationships between people have to grow as well. But, that growth has to encompass not only itself, but the growth in each individual. Only thing that should not change is committment. Once you are committed it oughtta not stop.
For me, I think qualifications are that this concept is understood. Otherwise, you're headed for disaster.
Not that I've actually managed this successfully of course. But, I've given it my best.