First and foremost, you cannot take care of your kids and your husband if you do not take care of yourself.

Your sister is completely out of line by 'inviting' herself and your mother to spend the summer with you. I can see why you are triggered by your family's dynamics. I'm betting this is only the tip of the iceberg.....

You may never get to the point where you can be around them period. I walked away from my mother and others. It was the hardest thing I ever had to do, but for the safety and happiness of myself and my family, it was my only choice. I don't feel the least bit guilty about it, either, because THEY were the ones who put me in this position by refusing to respect my boundaries and inability to treat me with respect, period.

It sounds like your sister/family are used to being able to tell you what to do when they want you to do it. I used to be that way. All mom had to do was say - insert order/wish/manipulation here - and I was off to the races, ready to please, so that hopefully, she wouldn't kill me. Everything I did at one time was out of pure terror.

Your husband hopefully will come to understand why you feel the way you do, but for now, he just needs to protect you until you've had some time to deal with this.

I know where you're at right now, and I know what I'm saying is probably scaring the hell out of you, and I truly hope the outcome of your situation will be better than mine in that you can eventually have a healthy relationship with everyone in your family. That didn't happen for me, but for what it's worth, I am a lot happier without them.

Good Luck