What to text when he says he's keeping his options open

This isn't rejection. It's a status update. He's saying 'I like you enough to tell you this instead of pretending, but you're not the only person I'm seeing.' That's honest. It also means you're not a priority.

The fact that he said it matters. Some people just ghost or string you along. He didn't. But the content matters more than the delivery. He's keeping options open because he hasn't decided you're worth closing them for, or because he's not the type to close them until things are very defined. Either way, your job is to figure out what you want to do with that information, not convince him to change his mind.

First, state your actual boundary. Not what you think sounds cool or what you think will make him reconsider. What do you actually want? Do you need him to stop seeing other people before you keep going? Are you fine with casual? Do you need more clarity on what this is? Say it once, clearly.

Second, leave room for his response without overexplaining. You're not negotiating a peace treaty. You're telling him what you need and letting him decide if he can give it. That's it. No follow-up questions, no long paragraphs about why you're worth his time, no false cheerfulness to seem chill.

Don't text back immediately. You're mad or hurt or confused. Wait until you actually know what you want, even if that takes a few hours. Then send one reply that says it.

If he doesn't respond or responds with something that doesn't answer your question, you have your answer. People who want to make it work will engage. They'll either agree to your boundary or tell you clearly they can't. If he goes quiet or gives you vague stuff, that's him telling you he's not going to change what he's doing. Stop texting after that. Don't follow up. Don't ask clarifying questions. Just move on.