The problem I have with threads like this is how much ammo gets levelled at the Mums - how they're so often the axis of all Step-mum's ire
In my case it's very 50/50.
50% her being purposefully awkward and at times purely nasty, and 50% how DH deals with that.
For example, there have been times that ex has been an absolute arsehole and DH has said and done the bare minimum (largely nothing) because he doesn't want to add fuel to the fire because there is a history of conflict with contact (in this case that translates to her trying to withdraw it and make it difficult for him to see DSC)
Ideally she wouldn't be so high conflict and he would have more of a backbone.
I've had to put up with a lot of shit, ranging from malicious SS reports to her sending DSC here with covid symptoms without being tested and failing to tell DH that for three days prior they've had a cough and temperature - whilst I was pregnant after multiple losses. I have no doubt that was a deliberate "fuck you"
The only courtesy I ever expected from her was that she let us know in advance, so at the very least we could arrange tests for them first, as I would expect DH to do for her if it were the other way round.
Demanding DH go and see DSC on the morning I was labouring at home, leaving me alone. Admittedly I insisted that he did go because like most of the time I was desperate to put them first, even to my detriment.
I've had abuse from her family for having the temerity to have a child of my own after being a (pretty good if I do say so myself) step parent to DSC for a lengthy period of time beforehand.
She spearheaded a smear campaign against me over Facebook which was as humiliating as it was childish.
Pissed up texts to DH ranging from abusive to sexually suggestive.
Trying to seduce him, to prove a point I assume.
Verbal abuse and disrespect from DSC which is clearly lead by her.
There is so much I'd be here all day.
I'm not suggesting that all first wives and girlfriends are this way, absolutely not, and she was perfectly pleasant to begin with but some women are like this and it makes it incredibly difficult to not develop some resentment (never toward the DSC themselves, just the situation)
I'm at the stage now where I'm seriously contemplating leaving because whilst things have settled down over the past couple of years I just can't see myself sacrificing any more years of happiness. I'm not yet 30 and feel like I have wasted the best years of my life, perhaps.
My life has become very small and I don't like the person all of this has turned me into when contrary to what some think about SM's, I really have tried my best.
Add in the typical nuances of having your life dictated by your husbands contact schedule and always having to consider DSC and ex, not being able to pursue certain things or make much needed life changes because it conflicts with the first family etc. It's all just too much.
Hats off to anybody who can deal with such a situation long term.