HE being the owner of the company and creator of the product (among others he has), do I ,as a joint venturer in this JV PRODUCT (being that I invested in half its cost for the ecommerce development of it to promote it) , have any say about getting revenues from his already existing customer base who want this JV PRODUCT?
If HE processes those sales through the ecommerce platform YOU created or co-created, I can't see why you should not get a percentage. But I agree with Charles that that kind of contract should be created with the professional help of a lawyer. Our opinions here will hardly be reliable advice in that case.

Ralf