yes, but Fio, didn't you know - ALL stepmothers are interfering busybodies who only want ot cause upset to ex's and children. they have absolutely no interest in working out a way forward, they exist purely to stop money, grab contact, and fuck around with everyone's lives.
all fathers, by default, are inferior to mothers. they are always wrong when a marriage/partnership fails. they are also always feckless non-resident parents, who are only interested in causing hurt and upset to their exes and children. they have no interest in seeing their children, and exist purely to hand over money and pay bills. they are not allowed any say in the upbringing of their children, nor are they allowed anythig aproaching normal contact and relatioonship with their children. they will, of course, be blamed for this at the same time (see earlier feckless non-resident parent comment)
honestly, the above is how the majority of the posters on this thread come across.
setting aside the OP's situation, where the father is not in any way to blame - blame is not a helpful thing in marriage breakdown, and it certainly should not be used against whoever is seen to be wrong - especially wrt children.
just because a parent does not make a good spouse, it doesn't mean they do not make a good parent.
giving birth to a child does not mean that everything you think/say/do wrt that child is completely and utterly unassailable.
equally, marrying into a stepfamily does not mean that everything you say or do is wrong, or doen purely to hurt the absent (and I mean absent as in not in your household) parent.
I have been messed around more times than I care to mention by dh's ex. she dared to suggest to the court that I was not fit to look after the children (I am a teacher, ffs, and thus CRB'd. her hints were that I was not a fit person, btw, not that I was not competent as a carer), which held up our case for contact for months while I was investigated. then, in the middle of all this, she suddenly realised she could not be bothered to drive her children to scotland, and casually suggested I should do so. on my own. so fine as a taxi driver, but not as a carer
then there was all the ridiculous business with the schoool, where my dsd was begging me to attend meetings. everyone was happy with this to begin with, I rearranged everything (as you do) to make this happen, cancelled seeing my family (which was important to me as they were visiting form abroad, and this was my only chance to see them) and then, when I arrived at the school I was told that the ex had complained about me, and that I was not allowed to contact the school about anything. in fact, wouldn't be allowed ot take dsd home (she was 13, and waiting for me - VERY embarrassed by this). the ironic thing about this was that dsd usually walked home (to her mum's house) but on this occasion, since a complaint had been made (god only knows what she said to the school) was not allowed to do that either, and had to wait for her (furious) mother to arrive form work - backfired a bit for the ex, that one.
anyway, I am ranting now, sorry
but please, please, can we drop the tired old act of "oh, a stepmother? yes, you must be acting out of spite and insecurity"
sometimes, there are very good reasons for wanting things which upset the other party.