My stepkids BM has many fine qualities and we have many overlapping standards and values. She runs a strict regime at her house and as a result kids are mainly well-behaved and any poor behaviour is largely just kid stuff. I do not doubt that she loves them.

However, my partner suspects that she has Borderline Personality Disorder - for a variety of reasons - and even though I went into this relationship really wanting to have a clean slate with BM and would have liked to reach out to her mom to mom, I think that is not possible and would make things awful. She rages when she is in one of her moods. She demands things of her kids that I don't think are appropriate and are a bit mini-husbandy - esp OSS12. She demands he brings her hot drinks in bed on weekend mornings - up two flights of stairs - when he asked why his brother doesn't have to do it, she raged. When he relented she threw the mug across the room - twice. She has done a lot of really emotionally manipulative stuff to him lately and has been reacting badly to his (admittedly) smart mouth and argumentative nature. He does what he's told - eventually - but he's an arguer - some of it is good arguing, like over historical opinion or whatever, some of it is the ridiculous 'logic' of a 12 yo boy. But this to the same woman who raged at my SO for days when he once told her "We'll have to agree to disagree." She felt that there simply could be no disagreement on any opinions of any kind. Her way is the only way. 

Lately OSS has been mentioning that she's screaming at him more and hitting him. I have not probed for details, but my ears prick up. No doubt this is when she loses control. The other day my son was complaining about me and my rules - kid stuff - doesn't bother me - heck I was thinking of getting myself one of those personalised mugs that say "Meanest mom in the world". OSS says "You have NO idea. Your mom is really nice to you." 

My son (11) says "It sounds like your mom is not a very good mom. I mean she yells at you and hits you..."

I about died. I immediately got on him and made him stop. My SO said "BM has many good qualities..." I said some things I like about her parenting. But I think our defense probably sounded a little feeble. 

It doesn't help that we've been really worried about the way she's handling things right now. And my SS told me at the previous visit (we only have them EOWE) that he was really glad it was Saturday and not Sunday because he didn't want to have to be at home as it was very stressful.