nailit - I can't agree.
The reasons for changes in behaviour are many and complex, and an attempt to sort them out can save heartache later.
For a species as sophisticated as ours, it's amazing that our ability to communicate with each other is still so backward - but we have what we have, and we persevere with it.
A relationship without communication is on its way out - trying to save it may work, but not trying will see it end anyway, so what's to lose apart from a little time and trouble? If a relationship is not worth that, then by all means move on.