Some mother-in-laws are sweet. They bake cookies for you and support your every decision. Others are bitter. They constantly talk bad about you and undermine your choices. If your mother-in-law is more like a monster-in-law, then this guide is for you!
Tell your spouse. This is the most important advice you can be given. If your spouse has no idea how you feel, they may put you in situations you'd rather not be in, like taking care of dear old Mom while she's sick. Tell your spouse kindly (remember, this is their mother) how you feel. State the facts, not your opinions. For example, if your mother-in-law tried to run you over with her SUV, say so. Don't say, "She's horrible and she wants to kill me!" Explain very clearly, without being rude and hurtful.
Discuss calmly. Ask your spouse how they feel about your mother. If the both of you are sharing opinions, it may allow you to be more honest. Don't freak out if your spouse hates your mother with a passion! Remember, if you're just finding out now, then obviously they've done a good job at hiding it. So expect them to continue hiding it around your family.
Be kind. Give your mother-in-law a break! For all you know, she was an orphan, or abused, or cheated on. She's human too, and has had problems in life just like you. Let's say she always griped and complained about your beloved green couch. You hated her for this and made your spouse's life miserable. Then she dies, and at her funeral you discover that she was raped on a green couch. Wouldn't you feel bad?
Get to know her. Ask her to lunch (if you're brave). Or the next time you're at her house, try to spend a few moments with her in the kitchen or sit near her and chat. If the conversation goes really bad, you can always get up to use the bathroom and sit back down in another chair!
When in doubt, give gifts. Women are complex creatures, true, but one thing is almost universal: we love presents! Christmas and birthdays, as well as Mother's Day, are obvious choices. Give your mother-in-law a gift from just you. If you have to, get your spouse to choose the present, then say it's from you. Make sure it's something she will enjoy. If she sees that you are thinking about her and know her tastes, it will help win her over.
Be included. Okay, so you know she doesn't like you and are pretty sure she knows that you don't like her. This doesn't mean you can just stop visiting. This is your spouse's mother, remember, and a mother is very important in life. Don't be rude when your wife or husband wants to visit his/her parents on a Saturday afternoon. You still need to let their child-parent relationship breathe. Visit with your spouse--don't make yourself scarce. Your in-laws will think you're a wuss. This will only make them dislike you more. Remember, the goal is to "get along" with your mother in law.