Everyone who has ever been in a long term relationship knows that they don't usually stay the same for long.We are always on the way somewhere and so are our relationships. There are many reasons why this happens. Sometimes just being a in loving relationship provides an element of safety that has been lacking and when we feel safe we begin to explore. That exploration can lead to all kinds of new perspectives and personal growth. So any good relationship can provide the platform for change.
There are other less wonderful reasons this happens also. If for some reason the differences that emerge over time feel too threatening to one of the partners, the result can be a pulling back from honest sharing. Few couples recognize or acknowledge how judgements and conflicts have served to close off communication and how these dynamics impact the overall experience of intimacy.
When couples gain a few insights into their emotional scripting and learn how to observe the differences in the images they carry without creating too much embarrassment, amazing new experiences of intimacy emerge. Conflicts become productive instead of destructive and intractable issues often find new solutions.