Love or ??

I have a perception --- that there is no love after marriage. It is a scary thought for me. Maybe I am wrong ( which I hope I am) but why is there a mundane feeling which seeps in after marriages? This I am saying irrespective of the fact that whether the marriage is a love or arranged one. Do people really fall out of love especially after marriage? What about people who choose to get their marriage arranged? I mean .. There is no love to begin with and then the couple may fall in love ( because technically they don't have a choice) and what after a few years when the warmth and hunky doriness fades out? I have yet to see a "love is forever" example.
One reason is probably that prior to marriages the lovers are not together and they long to be together. But once they are married and have spent enough time together, they get bored (?) or too habituated for each other.
Why is this love, marriage stuff so complicated at times? Maybe I can find out the answer only when I foray into it. But this is the exact reason why i would want to keep out of this.
Love can make a stranger dearer to me than anyone else. But arranged ? When my parents and his parents will ask us to stay together for an entire life? How will this stranger become dear to me? and his whole family? How will I consider his family as my family? Complications at their height!