Yes. The dealer committed a fraud on the lender and on you. The fact that the lender doesn't want to do anything about it indicates a close financial or working relationship probably exists between the two of them. And you are stuck in the middle. You should talk to an auto sales fraud lawyer right away. If you signed the finance contract at the dealership, then the dealer may have been acting as the legal agent for the lender when the deal occurred and that can help you legally. You need to talk to a local Consumer Law attorney who deals with this kind of case. Call your local attorney's Bar Association and ask for a referral to a Consumer Law attorney near you or you can go to this web site page for a Free Online 50 State National List of Consumer Law Lawyers (http://www.ohiolemonlaw.com/ocll-site/ocll-locate_local.shtml) and find one near you (lawyers don’t pay to get listed here and most of them are members of the only national association for Consumer Law lawyers, NACA.net). But act quickly because for every legal right you have, there is only a limited amount of time to actually file a lawsuit in court or your rights expire (it's called the statute of limitations), so don't waste your time getting to a Consumer Law attorney and finding out what your rights are. If this answer was helpful, please check the box below.
I assume that the bank has not come after you for the loan, and your boyfriend is making the payments. If he makes all the payments, you will be off the hook. The danger seems to be that he will default leaving you holding the bag. You raise two issues.
First is the fact that the loan agreement lists you as married. Note that if this is a fraud--that is if the fact whether you were married or not was material to the bank's decision to extend credit--then it is a fraud on the bank, not you. That means that they can "waive the fraud" and hold you to the contract. It sounds like that is what they are doing. There is no law that you have to be married to co-sign a loan. Theoretically, if the bank could show that the dealership made the misrepresentation and that it could not collect because you were not married, then it could go after the dealership for the unpaid loan.
The second issue is the dealership's apparently false representation that you could come off after a year. This could be what is called "fraud in the inducement" which means that you might have the right to rescind (cancel) your co-signature on the loan if you show that you would never have signed unless you knew it was only for a year. However, whether you could might depend on the relationship between the dealership and the bank, which is a matter too complex to get into here. Also remember that as a practical matter, liars lie, and the dealership would be unlikely to admit it said any such thing. (By the way, the next time someone tells you something like that to get you to sign something, ask them to show you where in the contract it says that. If it is not in the contract, write it in.)
Right now, if the boyfriend has not defaulted, it may not be worth doing much more than telling the Better Business Bureau about the transaction, or letting the Attorney General's consumer fraud division ( http://www.illinoisattorneygeneral.gov/consumers/ ) know about the dealership's lie about you being able to come off the loan and its misrepresentation to the bank. I also suspect you will not be patronizing that dealership again.
If there is a default, you may have a defense to payment or a claim against the dealership for its misrepresentation. If you have already been called upon to pay, or you want to get your name off the loan right now (is it hurting your credit rating?), you should see an attorney to explore your options. Many attorneys have free consultations to see if they can do anything for you. An attorney, might for example, find a statutory violation of the Illinois Consumer Fraud and Deceptive Business Practices Act, if you have sustained any damages.
Of course, you should not rely on this, or any other legal analysis you obtain in an internet forum like this. The only way to get real legal advice is to hire an attorney who can fully review the paperwork involved, delve into the factual situation and spend some time reviewing the issues.That is why the most frequent advice on this site is: get an attorney.