Kindly meant but your family are awful people and you are the family mug.
You know and understand your awful family but yet despite this being a lovely happy time, you hand over all the power to them to ruin this happy time, again.
Stop blaming them and take responsibility for being a doormat.
You are NOT being the bigger, better person here, you are just being a doormat.
This is your life, and the life you inflict on your new partner and children,
by being a doormat.
It must be really awful for THEM.
Take responsibility for this or NOTHING will change.
You need to grow up and step up and take a very firm stand.
Sadly your happiness means little to your parents, and your sister is just awful.
Yet you have allowed these awful people bring stress to your day, and your poor partner and children.
I feel very very sorry for them.
Why would you allow this to happen, when you know well what they are like?
Take responsibility for your part in this.
People pleasers are really awful to live with.
They take the easy way out and care little for their immediate family, while being used and tolerating awful behaviour from others around them.
Take control of this situation.
Cancel your parents and sister as they clearly don't care.
Enjoy your brother and your partners family.
Make the decision to step away from these awful people and begin your new marriage in a peaceful way.
Apologies if this sounds harsh, but enough is enough.