I am very concerned with the teenage brides that these fundamentalist cultures have been known to breed. I believe it is time for a reconsideration of what marriage is as a whole and our approach to its legality. As humans have begun to live longer and we are individually maturing emotionally at a slower rate. One hundred years ago it was appropriate for marriage at the age of eighteen (or in the case of some states like Montana, sixteen). However, I know from my own personal experience that I did not have the emotional or logical maturity at eighteen to make a lifetime bonding contract or understand the potential repercussions of breaking a contract.
My hypothesis is to allow unions between consenting adults over the age of twenty-one regardless of sexual preference or even number of partners. Marriage by clergy will no longer be recognized by government as a legal union. Marriage needs to be recognized as a legal binding contract with written contractual obligations. The document should state all expectations and obligations in writing for both parties and stipulate the conditions of any breach of contract. As far as I am aware, marriage is the only agreement that doesn’t spell out what it in it for both parties, yet when it is breached or nullified the parties are held to substantial ramifications. I believe that people would be far less likely to jump into marriage if they were fully aware of what they were jumping into. Should we increase the marriage age to twenty-one that would hopefully allow many would be teen brides to mature to an age where they are able to logically make decisions for themselves. Sex with a minor crime would increase to twenty-one as well (granted this won’t stop teenagers from doing what they do, but that is not the issue at hand). This move to change the legal marrying age to twenty-one would need to become nationwide. Yes it will take some adjustment, but we all eventually accepted the drinking law when it changed to twenty-one.
The Polygamist's Daughter 
I heard on the news the other night that marriage the way it is now is fast becoming a thing of the past. People more and more are choosing to not get married at all.
What you are describing with the legal contract is called a prenuptial agreement, and though some see it as a plan for divorce, others see it as guidelines to let them know where they stand entering into the legal partnership.
Either way, I agree that teen marriage is NOT a good or healthy thing. This is the voice of experience speaking… if I had it to do over again I would hope that I would not make that same mistake. My other option of being forced into a polygamist union however, made what I chose to do seem like a very good idea at the time.
My husband and I chose a post-nuptual agreement shortly after we were married as a way of protecting assets should something happen to one of us. If those entering into the marriage contract realize it is for their own awareness I believe that could actually strengthen the bond. It does not need to be as complicated as a prenuptual agreement but at least spell out what a marriage is and how it affects individual rights to property.
Marriage as a whole is a very antiquated system created as a means of bartering animals and daughters and adopted by religion as a means of contol. I understand all too well the reason for your teen marriage. I don’t know the details but I do know the panic of what it is to be “promised” to someone you despise and forced to face eternity with him. That is the reason I ran away at seventeen.