Its depends upon luck . if you get good girl then after marriege life is better but if girl is not good(behaviour point of view) then life will be like hell. That is the reason some people prefer love marriage.
Life after marriage is entirely different from before as we have a number of responsibilities after marriage.So it cannot be compared with pre.married life.
I life everything depends upon god and attitude, so if we behave according to the person who came in our life then life will be good after post marriage also