Law enforcement often has this opinion. The fact of the matter is, that is your residence. You kindly let him live there until now. You do not want him there any longer. It is your call. You do not have to let him stay.
However, if it will get violent and ugly, then it very likely has been violent and ugly before this. You need to get a protective order which will get him out and keep him out. If a person is violent and mean, a "kick out order" isn't going to make him any happier than packing his things when he is gone. This is not an easy situation. I have provided a link to an article telling about such orders.
A protective order is intended to prevent family violence by a member of a family or household (or former member of the household) by another member of the household that is intended to result in: * Physical harm, bodily injury or assault OR *A threat that reasonably places the member in fear of imminent physical harm, bodily injury or assault, excluding reasonable discipline of a child by a person having that duty OR * Abuse towards a child of the family or household.
A "Family" includes spouses, former spouses, brothers, sisters including those related by blood or marriage, biological parents of the same child without regard to marriage, a foster child and foster parents whether or not those individuals reside together.
A "Household" is a unit composed of persons living together in the same dwelling whether or not they are related to each other.
Contact the County DA's office in order to apply for such an order.
If you want to go ahead with the "kick out order" talk to your landlord, or just go to the courthouse and ask for the forms to proceed.