Can my boyfriend legally throw me out of our apartment?

Your boyfriend cannot just throw you out of your apartment. To evict someone from their established home, the person who is entitled to possession of the premises must sue in court. Since you were not on the lease, then you may be considered to be a "licensee" (typically that is someone who was invited to enter and remain on the premises for a period of longer than 30 days or more). Now that your "license" (or invitation) has been revoked you will need to be given formal notice to vacate. If in fact you are merely a "licensee", your roommate can serve you the notice.

However, you could be considered a "tenant", even though you have no lease. This could be accomplished for example, if the landlord has treated you as a tenant by accepting rent from you directly, by putting or allowing your name to be put on the mailbox, or if you and your roommate rented the place together and it was clear that both of you were on equal footing as to occupancy rights. Under any of these circumstances, you may have attained the status of a "tenant". In such case, the landlord would have to file for the eviction because only landlords can evict tenants.

Regardless of who evicts you, it is important that they comply with all legal requirements; this includes proper notice to vacate the premises. Someone who is put out of their home in an unlawful manner is entitled to recover damages against the wrongdoer. Furthermore, using illegal methods to force someone to move is a criminal violation. Therefore "self-help" measures 9such as removing your personal belongings or changing the locks) cannot be used.