I'd ask myself a blunt question: why do I need this guy? Why am I so attracted to this compelling idea? If you're a smart engineer, you can be the idea generator and the coder. That way you can retain full ownership, and then recruit the business guy. I'd reasses your approach to this potential partnership. Ideas and code are property of the business. Your compensation comes with equity and % ownership. I'd state clearly what each of you plans to contribute to the future of this venture, and how the two of you will work together to make this succeed. Ex. I will focus on engineering; he will be the biz guy who focuses on fundraising, handling investors, doing sales, crafting product vision, etc.