I have been living with my fiancée and his mother for about 2 months now and she wants me to leave I am not on the lease but she let me move in and didn't want me to go until her boyfriend made her is she leagally alwowed to do that

In most cases she must give you a 30 day notice to leave, if you don't leave she can then evict you which could be another 30days, 30 days of living hell if she is like most BF moms