When a guy wants to be exclusive with you?

Look at the verb. "I want to be exclusive" or "I don't want to see anyone else" is an offer, a statement of his own position. "Are you seeing anyone else?" or "Where do you see this going?" is a check. He wants information before he commits. Neither is a bad sign, but the first asks you to respond to what he wants, and the second asks you to respond to what you want.

Also notice what he's already done. If the two of you have been seeing each other weekly, making plans ahead, and talking about things beyond the present, the question is probably sincere and low stakes for him. If you've only been on three dates and he's asking for a formal commitment, slow down. He may be anxious rather than ready. Either way, the honest answer is still worth giving, but your pace can be different from his.

Most replies fall into one of three camps. The first is a clear yes. It confirms you want the same thing and that you aren't seeing anyone else. Keep it short, skip the hedging, and don't pile on conditions. The second is a conditional yes. You're open to exclusivity but want a little more time, or you want to raise something first, like how often you see each other. Name the condition without sounding like you're negotiating. The third is a not yet. You like him, but you're not ready to commit, and you say so kindly. It shouldn't sound like a rejection of him as a person.

What you leave out matters as much as what you include. A clear yes shouldn't carry a "but let's see how it goes" tail. A conditional yes shouldn't turn into a list of demands. A not yet shouldn't come with an apology or a long explanation of your history. You can tell a draft is working when he'd know your answer at a glance and wouldn't have to guess what you meant.

Exclusivity questions tend to show up late at night, when both of you are a little vulnerable and a little bolder than usual. Reply when you're awake and clear-headed, even if that means the next morning. A considered answer sent at 10am reads as more serious and more respectful than a fast one sent at midnight.

If he asks and you need a day to think, say so plainly: "Good question, let me think about it and I'll get back to you tomorrow." Then actually do it. If a few days pass with no word from you, he'll read the silence as a no, whatever you meant. If you still haven't decided after a week, tell him that directly. And if he doesn't respond to a clear, kind answer after a reasonable wait, he's shown you something about how he handles openness. It's fine to take that seriously.