I don't know anything about Ohio law, but:
Los Angeles city has a rent control ordinance saying that if an additional person moves in beyond the contracted number of people, then the rent controlled ceiling can be raised by 10% for each such additional person.
I have units in an area which is not within Los Angeles city limits and thus not subject to rent control. I often have tenants who want to add someone, and I charge an additional 10%. I cannot raise the rent during a lease, but if the lease says that only one person is entitled to live there, I can evict a tenant who violates that. Thus, I can negotiate on the basis of writing a new lease for 10% more and allowing 2 people, or eviction.
I hate to stand in the way of true love, but I am entitled to more money for the additional wear & tear.