I have acted as counsellor for a great many couples. This is of course a few years back when I was still within the "dating" age.
There was something very noticeable about the fights and the reasons for the fights.
It was almost always about why he or she "didn't change" or why they did.
If it was so easy to predict what changes were coming, then this world would be a more peaceful place.
Many relationships fail because one party tries to overpower another,or demands too much. People in love tend to think that love will conquer all and their spouses will change the bad habits after marriage. Actually, this is not the case.
There is a Chinese saying which carries the meaning that "It is easier to reshape a mountain or a river than a person's character."
It is not easy to change. Thus, having high expectation on changing the spouse character will cause disappointment and unpleasantness.
It would be less painful to change ourselves and lower our expectations. .