How to deal with a problematic sister-in-law?!

I think you need to confront her and tell her that her behavior is unacceptable. The fact is that you will both be a part of this family and will most likely share many functions and holidays together. It'd be best to get this done now instead of trying to "deal" with it later.

What does your FH have to say about it?

I think the first thing I would do is talk to your FMIL about what's going on so that your relationship is not damaged further. You might ask her to avoid the topic of you in conversation with your SIL, because it seems to turn into lies, and it isn't fair to you. If that is too uncomfortable, ask your FH to talk to his mom. He should be as upset about this as you. I would also ask your FH to talk to his brother about what's going on. I think your SIL could much more easily brush off what you say than what her husband says.

My sister-in-law is the same way. I asked her to be a bridesmaid and she has a fit about every guest my moh and I find. Moh and I decided on knee-length dresses since it is a beach wedding and sil is having a fit because it isn't all about her and what she wants. In-laws can be drama sometimes.

Lol i am almost in the same situation, just multiple it by 2.

Have your FH approach her and his mom about her behavior towards you. She'll be more likely to listen to him than to you.

SAME SITUATION GIRL, ughhh. I just try to ignore her when she's around honestly, I haven't come up with a good idea to handle the situation. Everyone gets upset if I say anything to her, even though she deserves everything that comes out of my mouth.

Sara, What i genuinely want to say is that no family is perfect in today's world,the only way to happiness is avoiding that tickle or most of the time handling it.Though your relation has been of 9 years it speaks for itself.

I'm in a similar situation, just not as extreme. Honestly....I let it go. No matter what I or FH said wouldn't stop whatever FSIL said about me. FMIL could either choose to listen to and believe her or not....again, us saying something wouldn't help. I ignored her and didn't play into her drama. It hurt FMIL and my relationship, but doing something (anything!) Would have made it worse. FMIL and I are better now, I think because I ignored the drama. I'm me...and if either of them want to trash me, they will no matter what. That's them.

I'd confront her. I'm not trying to get you going, but I just think that's unacceptable. If that was my FSIL, I'd either confront her or let my fiancé handle her. If she had any respect for her brother, she wouldn't be gossiping about you around the family. I wouldn't just let it go because then it will continue, and she'll think it's perfectly fine to continue her behavior.

Sara...ask her to lunch and chat with her (aka confront that idiot). Dont' give her an audience though. If there is someone else there besides the two of you...she'll go into "I'm the center of attendtion" mode (aka show her arse)

After you talk to her (regardless) of the outcome of the conversation, talk to the MIL...and reassure her that the relationship between you and the SASIL (that's silly ass sister in law) is good to go and after the wedding...pretend she doesn't exist until you have recognize she does...

Attention getters are that way out of insecurity and when they have reactions to their silliness...

Thank you Ladies for the advise.