It is important to have an operating agreement with any investors or partners. Do you have articles of incorporation?
Typically, when you seek new investment in the company, then you will need to either sell some of your shares or issue new shares which will dilute all the investors. Although selling new shares is common, you can't just do this without permission from other shareholders. That is why you need an operating agreement, which defines what you are able to do with or without a vote by the investors.
Do you have articles of incorporation or a description of your limited partnership?