Defer responsibility: Abuse is never justified so, you should never feel that it is your fault. Do not let the abuser overpower you and put the responsibility back on them. See if they are open to seeking professional help or at least taking responsibility for the abuse.
Set boundaries: Let the abuser know how hurtful their words are and discuss with them the fact that it is unacceptable to you. Set boundaries on what you will and will not accept from your abuser. Once you have set the boundaries, enforce those boundaries. Let the abuser understand that there are real consequences to overstepping boundaries.
Seek support: Attempt counseling, either together or separately. Surround yourself with a support system of family and friends and discuss with them what is happening and how you are feeling. Seeking support will give you the strength to do what is right for you and to carry out the 3 other steps towards healing.