This is a quaint attempt at definitions.
You go to a party and meet a man who's demeanor you find appealing – that's attraction. He asks your number, calls you on your lunch breaks and sends you random text messages for the rest of the day. If you blush and get giddy all the time, then most likely, that's infatuation.
Fast forward to a few days, weeks or months, the two of you are seen together holding hands in the movies or gazing dreamily at each other at the far corner of a nearly empty resto. Well, if it ain't official yet, then you call that MU or “It's Complicated." A simple profession of love makes it official and gives you authority to update your Facebook status to “In a Relationship” right on the very next day.
Subsequently, it takes a grande profession to move on to the next level. Engagement. The big day makes the two of you married and ready to live in your own fairytale called “Happily Ever After...” Until one day, after having tried a many million times over, you realized that there couldn't be such thing.
What do you do?