quick back ground... dp and i met online almost a year ago 
it soon became quite apparent that he had been in an abusive relationship for ten years. and was still sort of in it, still receiving abusive phone calls and texts and being screamed at in the street. any way we conducted our relationship pretty much away from that, he met my kids after a four months (by accident my ex h dropped them back early one day).
he was reluctant for me to meet his kids and i let it slide. his kids hid decision. (even though it left me feeling a bit insecure as i he had met mine etc)
then i got pregnant. he was booked in for a vasectomy so it was so not on the cards, but put a sudden time pressure on everything.
he still didnt want to tell his ex anything and didnt till i was 3 months (he admitted he was terrified of her reaction). he didnt tell her about me till then by which point we had been together for 10 months. she went mental.
she started to demand to meet me on my own, my phone number, my address were the kids went to school etc.
at first dp was inclined to say yes to her requests because he was just not use to saying no.i of course said NO, this would lead to hours of texting and phone calls, demanding her rights around her children etc.
she almost left the surface of the planet when she found out we were pregnant.
dp and i nearly broke up because i told him i didnt think he was ready to be out of his abusive relationship and having daily contact with an ex over a year after a break up was not normal, she uses the children to manipulate him in to giving her time and changing our plans.
he really opened his eyes to this though and is doing brilliantly now at telling her no and being strong though there are lapses cant beat 10yrs of conditioning over night. like the fact we are moving in together on Saturday "she does not want her children staying with a person she hasnt met" though i have stayed at his when they have been there and they have stayed at my house.
i would have been inclined to meet her earlier but to be honest i know she is going to make it difficult and the constant demands to meet alone for coffee to make her comfortable with the situation and the attempts to emotionally blackmail me in to doing so did not make me want to.
she has also demanded that my children and her children are not allowed to share a room for a year 
so getting to the point, my dp said she could drop the kids off at the new house and we could meet then (no consultation grr) know it had to happen though. he also says to me that she will want to come in and see were the children are sleeping so, her words "she can visualise", were they will be sleeping he said he had to do that at the beginning when he moved out.
i said NO.
will meet at the door step say hi nice to meet you bla bla what ever. the kids haven't even seen their rooms yet if they want to show them to her at some point (as my kids will prob want to show there dad) then maybe but she isnt the queen and she doesnt get to demand access to my house. he said to keep the peace we should otherwise it will become a thing. but it our house right? he doesnt get to go in to their house.
he has demurred and said i am right but i am now feeling very flustered about the whole thing.
god this is so long sorry all, i should be packing. thanks in advance if you manage to wade through it all.
was going to do aibu but felt i need a bit more experience rather than judgement.