why?

Why do relationships see a failure?
Is it because of expectations?
Is it because of possessiveness?
Is it because of fickle minds?
Is it because of commitment issues?
Can't love last for a life time?
Do people get bored with one person after sometime?
Once another interesting person is found, the previous doesn't seem appealing anymore?
Why do people cheat on their spouses? Lack of understanding/lack of love/lack of attention?
Is it that nobody wants to adjust or behave as per the mood of their partner?
It isn't losing their individuality, just a matter of accomodating each others' interests in a companionship and caring about each other.
Is it so difficult to love someone all the time and be in a blissful relationship?

How can someone leave spouse and what about the kids then? It isn't fair for the kids to be brought up by a single parent. Hmm...I wish I had the power to bind all the couples in the world blissfully together.