A 3yo will likely go with the flow as far as bedtime rituals and who ie "telling" them what to do. The 6yo might question it, but more from the prespective of where is daddy at versus why is this woman taking over at daddy's house. With children that young, they don't really compare who is doing what, just that they are being taken care of. In their lives all adults give them "orders". Dicipline should be as constant as the child's action. As long as it is dicipline and not abuse, be happy she cares enough to teach your children right and wrong.

I guess what I'm saying is, the children are in a good environment. There are horror stories where children are filthy, allowed to stay up til all hours, not read to, not loved. Your STBX may realize that he isn't good at the "mothering" of your children and allows his GF to do it in his place. When you see this woman, don't think of her as competition... think of her as the woman who cares enough to look after your children, not for pay, not for obligation, not for manipulation... but because she genuinely cares. I am a stepmomma... granted my DH had been divorced a few years before I came into his life. I have taken over the same activities... not to the exclusion of him, but to the help of him. Now the kids are 7 and 9 and bathe themselves and read to themselves. I still give them "orders" and dicipline them and love them. DH is a good father, but he didn't have a clue on how to raise productive future adults. He was reactive instead of proactive. The kids are very good kids, but they were sooooo scared of doing something "wrong" or "bad" their personalities were stiffled. The oldest has ASD, mild, but there. DH was just as afraid of doing "wrong" and he didn't see his overprotection was not protecting at all. The kids now have opninions, likes, dislikes and *gasp* misbehave. I love it. I want them to be confident, secure and leaders. I love them. I will get off my soapbox now... This woman as an asset to the betterment of your children she is no threat to your place in their lives... you are and always will be the momma.