Nobody enforces a non-circumvention clause over $6,000. Litigation costs more than the fee and the damages are speculative, so treat the clause as something that shapes behavior for people who intend to keep working with you and as worthless against someone who doesn't. That means the structure has to protect you rather than the remedy.
What that looks like in practice. Write the JV per deal, naming the property, the seller, the contract date and the split, instead of a blanket agreement covering "any deal introduced." Blanket agreements are where the arguments live. Include a non-circumvention term with a stated period, say 18 months, covering that seller and that property, and include a liquidated damages figure so you're not proving lost profit from scratch. An attorney in your state should draft it, because enforceability of liquidated damages is a state law question.
Then close the practical gap. He can verify the contract from the executed purchase agreement with the seller's contact details redacted, plus the escrow receipt for your deposit and the title company's file number. That satisfies a real operator. Someone who insists on the phone number before he'll show it to a single buyer is telling you something.
In some states you can record a memorandum of your purchase contract, which puts the world on notice of your interest and makes a quiet re-sign to someone else messy at title. Recording practice and whether a memorandum is accepted at all differ by state, and it can annoy the seller and cloud title in ways you may have to clear later, so ask before you file anything.
The thing more likely to cost you than betrayal is his buyer list being 400 names where 12 close. Ask which three properties his buyers actually bought and at what price, and go find out whether those closings happened.
