why most of the love marriage relationship are ended up soon after marriage?

Expectation my dear. Spouses do not get that response which they use to get prior to their marriage from other partner.

There is a big difference between love and true love. Love may initiate for greed of money of the partner, may initiate due to physical greed, may initiate due to any other circumstance. But True Love is really from the heart of each other without any greed or circumstance in or behind it. Love is a very strong bond which cannot be broken with the world's tougest force or the lover may die. This only happens in case of True Love. If a Love marriage is out of true love it will never break. But nowadays love is often taken as play within teenagers and there is no question of true love exists, mainly the physical attraction, sometimes monetary matter is in behind the love. This may be the main reason Love marriage are now often end up to divorce. But true love marriage still now exists. There are lot of such examples also.

Immaturity, if not befor marriage, at least after the marriage shown by both the partners equally well

Your premise is wrong - love marriages are not any less successful than arranged marriages. I have seen several successful love marriages, and several unsuccessful arranged marriages. Now coming to your question why love marriages break up - it is simple - if someone married against their parents' wishes, it is clear that they have their own mind and are not afraid of divorce if they feel it is really necessary. On the other hand, most people agree for arranged marriage simply because they don't have the guts to go against their parents. With such people, they will not divorce even if their marriage is a complete disaster, because their parents will not allow them to. Several people who have had arranged marriages have affairs outside their marriage to compensate for the mess at home. Sometimes both husband and wife have different affairs, but they will never divorce because of their parents and fear of the society.

The guy is never be same as before