"that's what I thought"
You are making no sense. Please don't be cryptic.
Why would you state that my faith wasn't complete?
Let's not forget the entirely "otherly-Gospel-like" Catholic Crusades which only managed to spare the entire continent of Europe from being under the thumb of Sharia since the 11th century. Better yet, the un-acceptance (followed by the acceptance) of Galileo's theory of the sun as the center of the universe which, as most Catholic-haters would like to say, is proof that the Church is bad, yet cannot state on what Biblical grounds they would speak differently of Galileo's theory at that point in time.
Without Reason, you've put God in a lockbox. Thomas Aquinas wrote his masterpiece on the Catholic faith based on a combination of scripture and reason. When someone makes a stupid, imbecilic comment like "[Catholicism] is illogical and from another Gospel", I guarantee you someone like me is going to come along and set them straight.
The reasoning behind anullment is that a marital commitment did not exist when the vows were made. I could be a philandering bisexual who can father ten kids in the next twenty years, and at the same time regard my wife as a spiritually unequal piece of meat, separate in God's eyes instead of united as a reflection of Christ's union with the Church. I could be a bigamist. I could marry with the unspoken intent of divorcing my wife when I hit my middle-age crisis. I could marry without intending to be faithful. I could pretend to believe in Christ for the sake of participating in a family-sponsored wedding, have my vows mean nothing when they spill from my lips, and become a Sunday school teacher later in life - but it doesn't make my marriage valid. If there is an ongoing pattern of physical or emotional or verbal abuse, the marriage is stands a good chance of being annulled, with or without kids.
There may not be anything "biblically" chapter-and-verse about annullment but the same can be said for any of the above scenarios with regards to "valid" marriage.