Yeah this is not right. What is the custody situation? If you are an involved stepmom, you absolutely need to be involved.
He is right but you’re not asking to never be inconvenienced, you’re asking for decision making to flow from your household out, not from him and his ex to you. That is reasonable. She should bring something to him and if it’s going to affect your marriage and your household the correct response to her should be, “let me get back to you. I need to talk to my wife.” Or just the first part and he talks to you. Men want as little over communication as possible but unfortunately having kids with multiple people is not the path of least resistance lol.
Giiiirl, the struggle. It’s all about communication and boundaries. Men seem to have a hard time with communicating with bms because they don’t want to ruffle feathers or cause conflict but don’t realize that it causes conflict within your home. You both are valid but when you’re in the weeds it’s hard seeing that. I would suggest talking as a couple about a compromise for different situations that may come up with the bm so when it happens you have a strategy in place to hopefully eliminate any confusion or disconnect. Ultimately he has to understand to weight of your concerns and you his to work to find a solution that’s works for all parties involved. If not this can definitely build resentment over time.
I've been through this so many times. If it's something small, I'm normally OK with changing the plans, but if it is something big, I stick to the original plan. My husband and stepdaughter use to get mad but after a while they got over. Now the moment we make plans and it involves my SD my husband let's BM and SD know.