He wants exclusive but told me not to tell anyone, what to say

When he says exclusive but no one can know, he's separating the commitment from the relationship itself. He wants you to behave like a girlfriend but without the visibility or social proof. This is often a sign he's either keeping other options open publicly, protecting himself from judgment, or testing whether you'll accept less than a real relationship.

Spot this: exclusivity only matters if it's real. If no one knows, then publicly he's single. That's the version of him that matters when he's around other people. Your reply needs to reflect that you see this gap.

A good reply points out the contradiction without accusation. You're not saying 'you're a liar' or 'you don't care about me'. You're saying 'this doesn't make sense to me' and 'I need something different'. The move is to state your reality clearly. You can't be in a secret relationship, or you won't keep a relationship hidden from people close to you, or exclusivity doesn't mean anything if it's not visible.

Then stop and wait for his response. Don't over-explain why you need openness. Don't defend yourself. Let him sit with the boundary and decide if he actually wants a real relationship or just the idea of one.

After you've named what you need, leave space for him to either agree to a real relationship or back away. Don't follow up for 48 hours minimum. If he comes back with 'I want to be exclusive and tell people', that's a different conversation. If he goes quiet or tries to convince you that the secrecy is temporary, you have your answer.

If he doesn't respond at all or dismisses your boundary, that's the moment to stop engaging. Silence after you've stated a clear need is a response in itself. Don't send a second message or convince him further. He knows what you said.