Disaster is a strong word Salma... I think that things work and I disagree... people do change. They grow and learn and sometimes even mature. Their life situations change.
I think that opposistes may work so long as their is a common ground in terms of core values and belief systems. SO long as one doesnt try to change the other.
I was in a relationship or two with opposites and I learned from both of them that I need to be true to myself. I never asked them to change but they constantly asked me to change implicitly and explicitly and this is why things went sour.
Also some of our lifestyle choices and thus belief structures were different which meant they didnt merge. We were similar in so many ways yes opposites in others too.
I guess what I am trying to say is that opposites can work with communications, growth undersatanding AND a common belief system and core values. What do you think Salma?