There is nothing wrong with asking this question before you decide to have sex with someone.
If you already had sex, I would ask ASAP.

I definitely recommend discussing this issue before sleeping with someone. I need to know that everyone is on the same page.

Dating rules really haven't changed much so don't be afraid to ask questions that are important to you for fear of scaring him off. The moment you do, you are compromising yourself, and that starts the cycle of self-doubt. The longer you invest in a compromised relationship, the more you'll compromise, in other areas, and the harder it becomes to break the pattern.

It's favorable to date someone who has a similar code of dating ethics. Dating someone with differing ethics, can put you in harm's way, and leave you with a bitter taste towards the delights of meeting someone new.

Don't be shy or awkward about it, just come right out and ask the question. You need not give any sort of reason as to why you're asking. If they ask why you're asking, then that says plenty if they can't figure out why you'd be asking.

Be strong and confident, don't allude to any of your past drama as your reason for asking, as that is what will send them skeddadling in a hurry.

When you both find each other interesting and wonderful enough to forego all others, and when time and energy prohibits you both from seeing others, I suppose!

If you feel like asking "Are we exclusive?", ask.

I personally, would need to have talk before we have sex...I am not ok having sex with someone, who may be having sex with other people. If there is a doubt whether they are exclusive/ monogamous (while intimate with me), I simply will not enjoy it. I'd rather be by myself if that were the case. But everyone is different, some don't care (are ok with it, as they feel it give them permission to seek it elsewhere too).

If you want something exclusive, tell him now. No you don't need to give him an ultimatum, but at a minimum tell him what you want, ask him what he wants, ask what he is willing to give you, and figure it out from there.

I would just talk to him about it. It doesn't hurt to talk about it... the only thing of course that might hurt is the outcome.

I hope whatever the result, you will find what you are looking for. :)

I would establish my roots further if I was you, give it three months, and then pop the question.

Exclusivity after a few weeks!?!?! Kinda crazy if you ask me. No wonder guys run away if most women want a commitment after a few weeks! Take your time and have fun before settling down. Geesh.

Play it cool, continue to get to know him. Let him be the one to ask about exclusivity. That's my opinion. I did hv about 1/2 dozen marriage proposals in my day.