Summarize this article:

This can be time before you will see your mother-in-law, or even during a family event. Take some time to be by yourself and reflect on how the relationship feels in the moment.  At a difficult family gathering, you can excuse yourself for a short walk around the block, or to make a phone call to a trusted friend. Before you see your mother-in-law, spend some time by yourself. You can use this time to reflect and relax so that you’ll have an easier time when you do see your mother-in-law. You may need to vent to a friend after spending time with your mother-in-law. Have someone on hand whom you can call if you need to. This step can seem drastic, but if your mother-in-law is truly abusive, moving may be the only viable option. Many couples do move based on proximity to in-laws. Living farther away can prevent meddling and unwanted visits.  If your mother-in-law’s abuse affects your children, moving away can help assure their safety from her. You can choose whether you and your spouse will be honest about the reason for moving or not. Sometimes, a spouse isn’t willing or able to admit that their mother is abusive. This can cause a rift between partners, and sometimes causes the relationship to end.  If your spouse can’t admit that their mother is abusive, offer to see a couple’s therapist together before deciding to end the marriage. Leaving a marriage is a big decision that shouldn’t be taken lightly. However, you should never tolerate abuse in order to preserve a marriage. If your mother-in-law has caused trauma for you or your children, you may want to see a therapist even after your mother-in-law is out of your life. Abuse can take years to recover from, even when the abuser is no longer a threat.  Even if your spouse doesn't see the abuse, you may still need to deal with its effects on you. Children can be affected by abuse even if they are not consciously aware of it. Make sure they have someone safe to talk to if they've been exposed to abusive behavior.

Summary:
Take time for yourself. Move to be farther away from her. Leave the relationship if necessary. Seek therapy for recovery if you need to.