IANAL, and, maybe I'm being pedantic, but it's not clear to me what the situation is: Your co-creator says that she wanted "100%"- did you agree to that? Did yo

IANAL, and, maybe I'm being pedantic, but it's not clear to me what the situation is: Your co-creator says that she wanted "100%"- did you agree to that? Did you have any further discussion with her about it? Without knowing her real motivations for wanting "100%" or why she would ask you to sign an NDA (as pointed out, usually something you do before someone reveals information to you) it would be hard to give further advice.... I think what you should be considering first is what YOU want- you seem to be inferring that you want to be acknowledged as "co-creator" and possibly some of the future profits of the app? Is she withholding any of these things from you now? Why? Given that it's not clear to me that you know what she wants or the motivations for her actions, asking her is the best way to find out. I'm going to read into the subtext of the post and say that the financial business relationship is what's important here, not your title on a form, so if you can come to an agreement on the former then you've solved your problem. If you do come to an agreement just make sure to get some record of it.