Mate, unless you have prior agreements that you have signed to the contrary, you own the IP. Period. You own it. Turn this around and invite her to 'share' in Y

Mate, unless you have prior agreements that you have signed to the contrary, you own the IP. Period. You own it. Turn this around and invite her to 'share' in YOUR IP. The fact that she is 'in charge of the business model' is immaterial. I've been in the software game for 30 years, and my advise is: never, never, never do anything that will reduce your ownership of IP. IP is your ticket. P.S. I am not a lawyer.