Long story short, I'm having problems with the (future) mother in law. I call her mother in law for short although the way she's going, she won't actually be one.
On Boxing Day me, my fiancee, the MIL and her equally vile husband went to visit her friend's house. During the end of the evening I went upstairs to go to the toilet. When I went back down I noticed that my handbag was open and when I sat next to MIL she turned her phone away from me as if she was hiding from me. It transpired that the MIL went through my handbag looking for painkillers. She thinks I've got an addiction. She found some strong painkillers. I'd only taken one of them a few days before because I had a migraine. I have fibromyalgia as well, which is a pain condition. I probably take more painkillers than an average person because I'm in pain, but she's made it clear that she thinks the whole fibromyalgia thing is a lie and that I'm using it as an excuse to hide my addiction. And the reason she was hiding what was on her phone is because she was reading up about painkiller addiction, and then she passed it to her friend so she could read up on it too. I questioned my fiancee about it later on and he told me what had happened. Because at the point it was happening, I could only really surmise. He said she was looking in my handbag for chocolate and just happened to find the painkillers. But why the fuck would she be looking for chocolate in my handbag? Her friend had got boxes of chocolates that she could have nibbled on. My fiancee also said she was just worried. Bull shit. She doesn't like me and will do anything or say anything to make me look bad. The horrible part? My fiancee just laps up all the bullshit she spews.
Rant over.
Get out. Get out now.
"The horrible part" is that you already know that this will be an ongoing rife in you and your fiance's life and if he's not seeing her for who she is and what she's trying to do to your relationship, then he's just as guilty as her.
Maybe he even feels the same way but doesn't admit it. Maybe not the lying about what you have, but the addiction part. Time to really take a look before you waste a lot of time being miserable mentally, while being miserable physically.
Just my 2 cents. 🌺

Get out now. That's several kinds of bad teetering on abusive.

Run away! Don't go anywhere near her.
No one has the right to go through your things. If she has a "problem" with you, she could've just approached you about it.
I agree with everyone else. RUN. Grab your shit and run. You don't deserve to be treated like that by either your future MIL or future husband. No one should be going through your purse unless you give them permission. No one should be touching anything of yours without permission.
If you don't walk away now, it will only get worse. It will be easier to make a cleanish break now than if you get married and decide to end it.
I'm sorry you're going through this
I gotta agree with some of these other comments sadly. If you're fiance doesn't believe you, or is on the road to believing his mother about you being addicted to drugs that seems very serious. If you can't make him see the truth of the matter, you should really ask yourself if you're prepared to spend the rest of your life constantly defending everything you do to not only your MIL but your fiance as well. Wishing you luck, since this isn't an easy problem...
I had to live with my MIL for 10 months and she's manipulative, says things about me that aren't true, controlling, abusive. She has it in her head that her son is the way he is because of me, not that, you know--he found a partner that's similar to him. He's atheist and doesn't want kids because of me, yeah ok. And don't get me started on my mom and my dad's mom. Christ.
Here is what I've noticed, when it comes to cis, opposite gender couples, the mother of the cis male is going to hate the cis girl. No idea why. All my friends, all my family. Hell my mom's mom didn't seem to like my uncle's wife either and she was a super sweet lady.
The other users saying "leave him" are looking at this naively. They don't know you, they don't know your relationship. It sounds like you must be really young if you're not married yet, so it could just be his inexperience with his mother's shitty behaviour, not seeing it from the outside. You might have to point out how her behaviour isn't okay.
Yikes. That behavior from your future MIL is completely inappropriate and frankly sounds abusive. I would definitely sit down and have a serious talk with your fiancee about it. You have no obligation to deal with someone who completely disrespects you and humiliates you like that. And you should make it clear to him that her behavior is highly inappropriate and disrespectful to you! If he can't understand that and support you, you might want to reconsider the strength of your relationship. It's definitely a red flag to me that he is making excuses for his mother like that, but obviously this is something you need to work out together.
If I leave you with any advice it would be this: Don't ever just accept shitty behavior from someone because "That's just how it is," or "That's just how they are." Be the change and point out when people are being inappropriate and disrespectful towards you. No one deserves that kind of treatment. Be strong and know that you can be the positive influence in your life.
Definitely do whatever you can to stay away from that awful woman! I hope your fiance can come around and start seeing through her bullshit but things like that take time because your MIL is probably a pro at gaslighting and other manipulation/abuse tactics.
There's a great sub on reddit for people who are going through or have gone through similar situations to yours. JustNoMIL is mostly people posting stories but there's a lot of discussion happening in the comments below each story and everyone is very supportive. I know it can be hard to find people who understand what it's like to go through stuff like this because abusers are able to make themselves look like angels to most people and gaslighting is a difficult concept.
I hope everything works out for you. :( Definitely don't let this take over your life. Most people say, "Well this is just how things are," and live in misery but you deserve so much better!
Hi guys, sorry for the late response! I ended up having an argument with my mother in law a few weeks back. I didn't shout, just told her what I truthfully, honestly thought about her and what she was doing, and that she was controlling both me and my partner. It didn't go down well at first. She was yelling, and crying, and dredging up her 'awful' past, probably to try and make me feel guilty. I believe she may be a narcissist so during the argument nothing I said really started to sink in, but after the dust had settled the whole atmosphere seems to be different now. We're never going to see eye to eye but it's definitely not as tense as it had been! I think maybe she realises I'm not a person she can walk over. Thank you for your responses everyone. I think you all had a part to play in me being brave and tackling this woman head on. Something definitely needed to be said!
I was going to post here and say you might just be dealing with a narcissist. :P So telling that she turned the conversation to make her seem like the victim with her awful past, to shine the light away from her bad behavior. That is one thing that always stands out to me; never do they accept any kind of responsibility, they always have an excuse or reason for everyone to feel bad and it's never their fault.
Have you looked at the Raised By Narcissists network on reddit? They have a great support group for spouses dealing with narcissistic inlaws! Link. I was on those threads all the time before my SO went no contact with the narcissist in his life. They will help maintain boundaries and have discussions with your fiance about how he needs to support you (and himself) and not be an enabler to his awful parents. Super great you were able to stand up for yourself, I can't imagine dealing with someone trying to make your chronic illness seem like an excuse. I'd get so mad. My only advice now is to remember not to back down in the future, and communicate with your SO constantly, it probably won't ever stop with her but do NOT have to play her games. As long as your fiance is supportive and also trying to come to terms with it himself you guys are good to go. An uphill battle, take care of yourself.