Am I in the wrong?

I've been with my SO for almost 6 years.

A little back story . I was best friends with his sister in law . That is how we met . His sister in law and I were really close in the beginning until my SO and I became serious . I was always there for her . Get together, family events , when she miscarried and hurt her leg I was thoughtful ( helped get groceries , thoughtful gifts when she mourned and would drop by just to say hello and bring a coffee . She began getting distant . Everytime it would be her turn to host a holiday at her home it started feeling like she didn’t want us around . ( dirty looks , complaints, my kids weren’t allowed to sit on her couch ) planning girls outings where I was not being included really hurt my feelings because I would have never done that to her . It started feeling like I was the only one who wanted a friendship . Phone calls were never reciprocated , when I broke my ankle I recieved 1quick phone call .

Fast forward I got engaged a year ago and asked her to be my bridesmaid in January. This is where is became even more clear she didn’t care to be my friend . No calls. No questions about the wedding . Nothing . Im a very sensitive person with a huge heart .

Fast forward to September we were all at a cottage for my MIL birthday . Her daughter told my Daughter she wasn’t family and was a bad cousin . I was hurt but held it in for the sake of not ruining the party . Nobody stood up for us and said anything . No apology to my Daughter . No explanation. My SO told his brother what had happened and nothing came of it .

The following week was my Daughter’s birthday . They said they were sick. ( understandable .) Here we are 2 months later . No happy birthday . No card . Nothing .
This past weekend was my sons birthday . We invited them for dinner and cake along with other relatives . A week ago my SO sister in law removed myself and my sweet Grandmother off her fb . Ok . We never said anything . Nor did anything for this . But let it go .
They arrived 1hour and 35 minutes late for the party .
Missed dinner and all .

She came to my home . Did not look or speak to me . Completely ignored my entire family .

To top it off my SO is an alcoholic. He has been completely sober for 3 months and made it clear to everyone including his brother no alcohol at our home for those reasons . Well his wife decided to show up with a beer in her hand at our home !!!

I was baffled and hurt to say the least . Nobody said anything . Everyone is scared to make them mad . I find it extremely disrespectful.
I am sick and tired of being treated this way and im sick and tired of nobody saying anything !!!
I let it go for my sons birthday party . I woke up the next morning with it still bothering me . I texted her and told her how disrespectful that was knowing no alcohol allowed here and to never bring it to our home again . Well now I’m the bad one because they are mad because I should have said something in person.

I’m sick and tired of being the only one now that is tired of allowing this toxic behavior and im tired of my SO not having my back and allowing her to treat my kids and I like this .

The blame is now on me . Its always deflected away from them . So instead of dealing with the real problem we are now dealing with the problem of me reacting by text message when I shouldn’t even be the one having to deal with it. My SO should be putting a stop to it but he’s scared to lose his brother. I feel this is so unfair and hurtful because I don’t deserve this treatment.

FYI she doesn’t like his sister or husband’s parents either .

Am I wrong for being upset ? Or should my SO be stepping up and putting a stop to this ? I do not want my SO to fight with his brother nor become estranged . But after being together for 6 years , now engaged with children , am I asking to much for him to stand up for us and tell them its not ok how they are treating us and that his brothers wife needs to put an end to all of this drama and hurt . Part of me feels like he should care how I’m being treated and not allow it