There's a pretty short list of what is considered acceptable grounds for annulment.
You might believe that, but practice is a bit different. My parents were married for six years, then (civilly) divorced. Two years later, they remarried each other (I have no comment on how smart my parents are) or, in the Catholic view, "renewed their vows." This marriage lasted another two years or so before they separated for good (the divorce followed along a couple of years later).
Fast forward a decade and a half, and my father (who in the interim married a second wife and had a second divorce) wants to marry a devout Catholic who refuses to marry outside of the Church. My father was able to obtain an annulment despite the opposition of my mother, her family, and my father's entire family (my grandmother (dad's mom) felt strongly enough about it to write letters to an archbishop and a cardinal). The archdiocese of Oakland saw no reason not to grant the annulment, and did so.
While I do wish my father domestic happiness, the result here is completely absurd, and goes to show that if you send enough money the church's way, morality is flexible.