How do you deal with feelings of absolute hatred towards your SC’s mum?
To be clear I have been with my DP for 5 years, I have a lovely relationship with my SCs. I have never really had much contact with their mum other than polite chit chat at pick ups and drop offs, all started off very nice etc.
I keep myself to myself and do not get involved in anything to do with the SC’s arrangements between parents.
I actually thought their mum was nice and up until 18 months ago I wouldn’t have had much of an opinion about her either way. I even would stick up for her when DP would vent to me about certain situations and I would always try and get him to see things from her point of view as I am also the RP for my own children from a previous relationship.
We all rubbed along ok.
However, my problems started about 18 months ago when she began dating the ExH of one of my close friends. My friend and her ExH do not get along at all and had a very lengthy and brutal custody battle. He was verbally and mentally abusive.
In summary, he is not a very nice man and it has transpired he actually has children by 3 different women, the youngest of which being with my friend. She knew nothing of the other 2 children as he denied paternity up until recently.
Anyway, SC’s mum has immersed herself into the drama which has ensued and has taken exception to my friendship with her DP’s ex whom I have know for over a decade.
She consistently calls me names, sends messages filled with vitriol about me to my DP, posts things on SM, has started saying awful things about me, my appearance etc and calling me a snob to my SC.
I have done nothing to provoke this, it is all because her and her current partner do not like the fact I’m friends with his ex. Even though both my relationship with DP and friendship with my friend far predate their own relationship.
The things she said about me are incredibly hurtful and mean insults and I’m struggling to get past them.
I hate her. I have never really hated anyone in my life but I feel like my anger towards her is eating me up and every time she is mentioned or my DP goes out of his way to help her I am filled with an overwhelming rage.
I do not show this in front of my SCs, I am so lovely about her in conversation with them and have always taken the high road. But I know she’s bad mouthing me to the children and in front of them because they repeat things she’s said and I’ve also heard them in the background when she’s rang DP in one of her tempers.
I don’t know what to do. It’s got to the point where I resent helping her out at all. She rang DP today asking to switch days for contact as she has plans and it’s resulted in my being cross with DP for thinking about accommodating it because I honestly just think “fuck you, why should we be nice?”
How can I move past my hatred of her 
She’s honestly vile. It’s breaking my heart