My question involves collection proceedings in the State of: Maryland

I made the mistake of cosigning my daughter's student loans in in the early 1990's. Interest has been accruing since then as she has been in forbearance for various reasons. She is now graduating and moving in with her boyfriend. If he agrees, is it possible for him to substitute his name for mine as co-signer either outright or through refinancing the loans? I am now retired with no income other than pensions and my credit is being decimated by the debt to income ratio that shows on my credit report because of her loan. Also, if they marry, does he then become responsible automatically?