Can I really trust my ex's sister? Or am I being played for a fool?

I have a dilema. I broke up with my ex-fiancee 6 months ago and for the first time I feel ok in the past few weeks.. I've had to get over him cheating on me multiple times, destroying my sanity and self-worth, abusing me emotionally, getting an abortion, losing myself for a while, the emberassement of cancelling a wedding...etc etc etc I could go on for ever. He is also expecting a baby with one of the several women he cheated on me with....they are living together now. (took him just a month to move on while I barely made it through) It has been hard to say the least.

Throughout this entire hardship, I remained close friends with his sister. He has done her wrong many times. He has even stolen from her. When I first moved in with him she came over and even warned me about him and told me many bad things about him and what he has done in the past to women..this was before him and I even had any major problems so this is why I always felt like I could trust her.. the closer we became, the more stuff she would tell me about him . They barely ever spoke but when they did she was very fake nice to his face..she always told me it was because she wanted to avoid family drama since he is very confrontational and the mother always takes his side (they have some weird rivalry going on from young..the mother is a psycho who always takes his side...she is obssessed with him and favors him and caters to his every need even though he is in his 30s she has even told me before that it's MY fault he cheated on me..puke!)

While I was with him, his sis and him barely ever hung out but her and I became extremely close. However, one time we went over to my in-laws for Christmas (him and I were doing well at the time) she got annoyed that my mom was talking to her parents the entire night and that "I was with him at the dinner table the whole night" (our parents were meeting for the first time it was nerve-racking...plus we were about to announce our engagement..which never ended up happening because of all the drama) I thought her attitude was way out of line. She decided to cuss me out downstairs and start a fight. The whole family heard and it ruined my night! Her brother blamed the whole thing on me when we came home so him and I fought too! She also send me a bunch of extremely rude texts after.. We had a falling-out after that but became close again later.

The final break-up was this March and she was really there for me the first few weeks after. She took me out and refused my money, she took me to a concert, she talked to me a bunch of nights for hours on end. Then him and I decided to meet up to have a "closure convo" and he brought up some things in the conversation THAT ONLY HIS SISTER could have told him.. she was the only one that knew...but he made it seem like he just guessed. That's when I started becoming suspicious. A few weeks later she tells me that he told her he wants me back and is desperate to talk to me and that he is going to go to sex rehab..but instead I find out he's already dating that girl that he got pregnant! (she wasn't pregnant at the time) It was very hard on me. Especially since I got my hopes up after what the sister told me. Months of crying go by and his sister and I remain close. She always tells me they never talk unless he asks her about me or how I'm doing and even then it's rare. She also gives me dirt on him (that she says she hears from their other brother) ..like how he's treating his new gf like * * * * too or how his new gf is so ugly etc

I have to add at this point that their mom hates my guts! Always has..along with any woman he dates because he is the king in her eyes and noone is good enough. So I know for a fact that the parents don't approve of her and I's friendhsip and as a result, she hides how close we actually are. (I can sense it from some things she says, or when she doesn't answer the phone if she's with her mom etc etc) This summer, I went to her son's b-day bbq. She told me it would just be moms with kids and close friends. Her parents came. She also told me her brother was not invited because she did not approve of the girl he's dating and the whole baby thing.. he came anyway but without his new gf and I never saw his sister react in any "shocked" way. At the party..she kept calling me her "assistant" and making it seem like I was only there to help her out. Her attitude towards me changed when her parents got there and when her dad called me a bad name in their language (which I understood) she never said a word... she also freaked out on me in front of her brother because I didn't get my camera out in time to take a photo of her son blowing out the candles (what am I her slave?) and he laughed at me under his breath..I WAS MORTIFIED! Not exactly the way you want to look the first time you run into your ex after a huge break-up and cheating involved no?

Again, I distanced myself from her and again we became close about 2 months ago and she has been extremely nice to me since...no complaints! Then recently, we all went to a club together and she started being a b**** again and talking down to me in front of her group of friends (whom I didn't know, and whom she is not really friends with..it's obvious she uses them for hook ups at this very high end club we all go to) These people were a bunch of pretentious snots and it's like she was trying to be like them and kept putting me down. She even told them that she gave me the Gucci handbag I was wearing!!! She effin knows that I don't have expensive clothes because school has cost me a lot of money and my family is back home in Spain and my parents were immigrants so we don't have the same lifestyle as them...she knows this and she still points out she gave me that Gucci bag! (it was a hand-me-down) What was the purpose of that?? I still ended up having fun at the end of the night but she put a bad taste in my mouth. Her brother used to put me down and talk down to me too..like he thought he was better than me or something! Even though he was an outlaw, a cheater, a liar, and couldn't hold down a job..and even though all the girls he cheated with looked like trolls and I'm very attractive!

Bottom line... I am trying to decide what to do with this friendship. On one hand, she has done SO MUCH FOR ME. I can't count how many times she took me out for dinners or drinks and refused my money..before and after I broke up with her bro. (she knew I was a student and she makes decent money and owns her own house already) She has also supported me emotionally may times though hardship..and we have also beenf riends for 3 years now. I feel bad leaving our friendship after all she's done for me. But on the other hand, these little episodes she's had have a hint of cruelty to them.... anyone else see that?
What do I do? Somebody please please help me make sense of all this. Am I overreacting?

I think that you need each other in a not so healthy way. She uses you to feel better about herself (treating you like an assistant, the Gucci thing), which is not friendly at all and you use her as an emotional cane. It is true that she was good to you many times, but you can't stay quiet because of that. She is helping you to make you feel as if you owe her something, so that she can bitch you out whenever she needs, as a punching bag.

You have to make her realize what she is doing and tell her that you will not stand her attitude towards you and wish to be friends with her without the frenemy thing. If she really likes you, she will respect you and that is it.

I told you in your other thread that I thought you should distance yourself from her because she was in the middle and relaying information about the asshole you pine over which was keeping you stagnated and thinking about him all the time. the whole family (if what you say is true) sounds psycho. I suggest (again) that you Distance yourself from ALL of them.

P.S. You need to learn how to be a little more assertive and stop taking crap from people by firmly yet calmly telling them "No."