I'm only engaged so far with my wedding still 4 months away.

I read up on Bipolar disorder and realised my Mother-in-law displays all the symptoms. I know breaking the news to my fiance or his family will only get a bad reaction against me and it would be best if i keep quiet for the first few years of my marriage atleast.

So without any possibility of treatment, I really need to figure out how I can manage my relationship with her so that I do not keep getting hurt.

Any one time when I interact with her she will be super happy to be around me and keep saying how much she loves me and asking if I love her too. The next time she will be horrible and will insult me in front of everyone repeatedly. I am not completely over the pain of the last interactions insults and she starts acting like I mean everything to her. And she expects me to reciprocate her emotions but I can only bring myself to be polite.

She is extremely judgmental and opinionated and passes judgement on everyone icluding her own children. Now, even if she may not say anything about me, i have started to take her comments negatively and that makes it even more difficult for me to like her. She also keeps trying to force me to join her religious group. She gets very hassled and keeps asking me why i dont show interest.

I have repeatedly forgiven her and tried my level best to be nice and polite. But I know that I must be sending out vibes of how much I hate being there with her. There has been one time when she provoked me by calling my mother stupid and I ended up answering her back( though not shouting or being rude). This only made her flare up and say more direct horrible things about me and my family. It has been very difficult to forget those words of hers. I realize that I should have moved away instead of stay there and answer back. My fiance is not the most supportive although he tries to be. I still feel he thinks I over react whereas I always try to cut down the display of pain. There was a point where I thought the wedding would be called off.

The plus points are that my fiance loves me very much. My father-in-law is the complete opposite and is wonderful in managing relationships. Also, Since my fiance works abroad there wont be a very regular interaction with her.

But I dread the days of the wedding and vaction times which I will have to spend with her. Pls tell me how best I can manage this relationship.