murali u r right understanding is must in a relationship and i would also want to include dat accepting and living wid ones nature is also must. i have noticed in many marriages they play win-lose game instead of win-win. they fight on whether the frame should be here or there. They try to impose their likenesss and dislikes on da other widout notice instead of letting him/her know or give advice, trying to change the other self instead of self. and most common i have seen they treat each other wid no respect as if taking each other for granted.
i have noticed these in every type of marriage.