If you ask him to get help and he still refuses there may be nothing else you can do. You cannot force anyone into treatment. You may need to consider whether or not you want to stay in a relationship with an individual who knows he needs help but still refuses it.
You said he gets angry at you for small matters. He not only gets angry but he then throws you out of the house. His anger is targeted at you and he essentially blames you for his problems.
You did not say how long you have tolerated this behavior. You mentioned that you have been living together for three years and that perhaps you love your boyfriend “too much.” I am taking this “too much” expression to mean that you may feel that your excessive love for him has allowed you to tolerate abusive behavior from your boyfriend. It is fine to love your boyfriend and to want to help him but if you try and he repeatedly refuses your suggestion for help, it may be time for an ultimatum.
My advice is this: Ask him to get help and if continues to say no, you may want to consider a separation until he does. The alternative is to continue living with a person who knowingly hurts and abuses you. Your staying with him may actually “enable” him to stay away from treatment. Certainly, he feels no need to change his behavior towards you, after all “you must be ok with it or you would have left him.” All enablers are well intended but they allow the problem to continue and thus actually hurt the person they are trying to help.