Am I wrong for feeling this way?

So my husband and I have two children and he has a daughter from a previous relationship. We agreed that my step daughter would come in June because July would just be too much and I wanted to rest and relax before having our son. June comes around and her mom starts acting crazy and doesn’t allow us to get her. Today rolls around and he calls me from work telling me that she will be coming tomorrow with my father in law since her mom agreed she could come. Am I wrong for being pissed off about this? I feel as though he should’ve discussed it with me also and that her mom is doing this on purpose since she knows I am now being induced on Monday. He’s saying that I’m wrong for being upset about her coming but I had no plans on having to take on a third child while I’m this far along in my pregnancy. Our girls are 5 and 7 and my step daughter is about to be 11 but she acts like she is their age. Not to mention I don’t trust her alone with my girls. The last time she came she almost drowned my 5 year old in the bathtub, the time before that she dropped a big dresser on my five year old and didn’t even tell me, my 7 year old cake and told me. He says he’s upset because her mom gives him a hard time and I should be more understanding. I’m trying to but Idk if it’s my hormones being all out of whack. I wanted to wait until we got settled in with our son for at least a week and try to get my step daughter for a weekend. Now I’m feeling stressed out because I’m going to have to keep an eye on her at all times so she doesn’t try to hurt my 5 year old 🤦🏽‍♀️. Am I being wrong or unreasonable?

UPDATE:

Thank you ladies for your response. He apparently already told her that she could come and confirmed everything with her and her mom rather than asking if she could come another time. He agreed to take a week off in order to keep an eye on her and he said that my father in law will watch her while he is here as well. I don’t feel as though this will work and he isn’t hearing me out at all. He was suppose to be taking a week of to help me get adjusted and spend time with baby so I’m not sure how he is going to get any time in with her. I’m really upset about it and I’ve just thrown in the towel on the subject and don’t even want to discuss it. He doesn’t feel it’s fair for my parents to be here and his dad to be here for the birth of our son and not her. I explained to him that they are going to be her to help around the house and with the other girls. I feel more comfortable with them being around especially knowing she’s coming so there will be more eyes on her, but I feel he is selling her short with her coming around the time time he is taking off to bond with our son so if she was jealous before I’m pretty sure she will be jealous more now that he won’t be giving her his undivided attention while she is visiting. I do agree with one individual that commented and I’ve told him that she really needs to get help. Her mom claims she’s in counseling but she lies a lot so I don’t believe it.