You need to give a proper written notice within the required time that you are not extending the lease and are vacating the premises. You cannot force the other tenant to leave but the landlord cannot force you to continue to be a lessee either. Once you have given proper notice make sure the landlord knows your boyfriend may or may not intend on entering a NEW lease with them but you have no intention of extending your lease either as a month to month tenancy or a fixed term lease.

