need advice

my boyfriend and I have been together for 3 years and he has two daughters from a previous relationship. I love his girls and I raise them as my own but we do co-parent with his ex and her boyfriend. I love his ex and I get along with her well. we do have our moments but that's to be expected.

one of the issues that I have is that she will schedule the girls for events while we have them and expect me to handle it without asking first. now I do because I don't mind doing anything that will make the girls happy but it irritates me that she can't ask out of courtesy.

currently my boyfriend and I are talking about having our own child but I am having a hard time adjusting to the idea. it upsets me a lot that he is already been through two births and raising two daughters and this will not be his first time as it will be my first child. I feel like I'm going to be missing out on an experience with someone since he is already gone through this with someone. I'm also worried about the dynamic between his ex and I once I have a child and if she continues to just schedule things without asking and I now have another person to think of.

I'm also worried about having enough time to spend with my first child while raising his two daughters. I don't want them to feel left out under black dude and I don't want my child to feel left out or neglected either. I feel like I'm missing out on that experience of having a first child because of already having two stepdaughters that I raise as well. we only have the girls every other week for the full week which makes me more worried that they'll feel neglected compared to a child that is with us full time.

I'm just looking for any advice for anyone who has been through this or something similar. I'm not sure if I'm just blowing it out of proportion or if there's a way to get over this or think of it differently.

thank you to all who read an offer any advice.