Please forgive me if I make a few assumptions here -
The guy is divorced
You two started a physical relationship fairly soon
It's hard enough just to get a guy to have the "talk" - and usually non-productive to even try. If their physical needs are already being met I'm not sure they even understand why we have to "get into" it.
If you're feeling driven to have the talk I would REALLY recommend waiting. And if you still feel driven I would find a very NON-traditional way to get your point across.
Because it is NOT whether HE is ready to commit. You would already know it if he was.
It is a need to let him know how you feel. That YOU are ready to emotionally pair off rather than just physically.
Just a note though that any reference to the "C" word may have him backpedaling - 3 months is a pretty short timeframe for some people to be a part of a couple.
And take into account how long since his last relationship?
And the death of an immediate family member?
I DO believe in setting a time frame in which to see some sign that someone wants to be exclusive - but NO guy that I know responds well to being sat down & told "We need to talk". They close up tighter than a clam - they can't help it.
Are you needing to know this now because you intend to break it off sooner than later if he isn't interested in a long term relationship?
I'll tell you that I was 35 when I met my husband. I'd had short relationships and long ones. But when Mr. Ruth met me he KNEW. There was no need for me to "make" him tell me it was going somewhere. It was obvious.
My experience may get in the way of understanding the point of having the talk at all!