Life isn’t always easy, and it is not perfect either so if you have a difficult mother 

• Talk to your partner- First things first, a difficult mother in law will put pressure on your relationship especially if your partner is happily ignorant of the situation. If the situation is hard, you will need to tell your partner and be honest about the issues. Of course, be tactile as remember this is his/her mother and no one wants their parents being vilified. An honest conversation is needed but not too honest either that you push your loving partner away!
• Look at the issues objectively- Try and keep an open mind, look at the issue and be objective. Is there something that happened in the past that triggered this problem? Can you see your mother in laws point? Or is she just being plain difficult? Right now, you need to be honest with yourself and if you stepped out of line you may need to apologise to move on in a positive manner.
• Try and resolve the problem- Once you have figured out the problem, you should work to resolve the problem as amicably as possible. You may have to be the bigger person, maybe not? But you must try and sort this for your family’s sake and especially your partners sake.
• Don’t be dragged into arguments- Avoid being dragged into an argument and be the better person who walks away if things get heated. Ask your partner to be there while you and your mother in law discuss or another close family member to keep everything running smooth. If your mother in law is difficult as a rule you may have to change your thinking and accept the relationship will never be easy between both of you.
• Avoid her if you need to at times- There is nothing wrong with avoiding her if she stresses you out or if she has an extremely negative effect on your mood. That is not to say that you can avoid her all the time but pick your moments and pick your battles carefully.
• Refuse to be toxic- Refuse to be the person that other talk about behind your back as you don’t have to be like that. Though your mother in law may choose to be toxic you certainly don’t have to be. This isn’t a child’s game of tit for tat so be mature and the bigger person.
• Work on it- Most relationships have their ups and downs so accept that you and your mother in law may always have an issue and it may take a lot of work. If you love your partner and your family it may be a consequence of that but handling it well will see you right.