Does either IN or MI recognize common law marriage?

I am sorry for your loss. Indiana and Michigan do not recognize Common Law marriage status.  Generally the following states recognize it: Alabama, Colorado, Iowa, Kansas, Montana, Rhode Island, and South Carolina.  The following states recognized common law marriage prior to a date certain that was determined by the legislature but not now: Georgia, Indiana, New Hampshire (for inheritance purposes only), Ohio, Oklahoma (maybe; the law is conflicting) and Pennsylvania.

I understand that you want to know what your rights are to his estate.  If he died without a Will and you are not a person under the intestacy statutes that would inherit then you will probably not benefit from his estate.  If he had a Will and you are mentioned then his Will should be given deference by the Court.  Also, if there is a life insurance policy that names you as a beneficiary then that would stand as well.  That may be the case for joint bank account that have a POD (payable on death) form properly executed.   Only an attorney in your area who can sit and look at the situation  and what you held separate and together can help you determine what you are entitled to.  Seek legal help.