can I file a discrimination lawsuit against my landlord?

First thing is to do some research and know your rights.  As a tenant, you have a right to "quiet enjoyment" of the rental.  It sounds to me like the landlord may be violating that right if your boyfriend is just visiting.  Do you have a written lease?  If so, review it.  A landlord can impose conditions like advance notice before throwing a party or guests can't stay for longer than a week without landlord consent, but if there are no terms in your lease limiting your boyfriend's visits, and he isn't breaking the law or engaging in disruptive or dangerous behavior on the premises that might endanger others, the landlord cannot impose such conditions later.  Along the same lines, as long as your boyfriend behaves when he visits, then you have a right to privacy that the landlord must respect. Where this gets tricky is if your boyfriend is spending most nights there, receives mail there, has belongings there, etc., then the landlord could make an argument that it is an illegal sublet. This is more of a landlord/tenant case than a discrimination case, unless of course, you reasonably believe the landlord is behaving this way because of your disability, your daughter's disability, etc.  Is your boyfriend also disabled? If this is a northern California case, contact me.  I would be happy to discuss it further.