Thanks everyone for your advice, you have all been very understanding and sincere. It is much appreciated
Since our initial discussion of what each of us wants in general and specifically, he has continued to invite me to his place and to gatherings with his friends etc and he came to a party with my friends last night, so he certainly doesn't seem phased by anything so far. He is the one initiating the contact too, so I don't think I can see myself as pushing things. In addition, he says that he's not really interested in seeing the other shagbuddy very much anymore.
You are all correct of course! Three weeks is not long - I do realise this! I had been referring to it as the 'sex haze', but NRE sums it up nicely as well
The amount of time we are spending together is complicated by the fact that I have been off work and stufy for awhile due to an injury - in my normal life I work 100 hour weeks, and will be going back to this shortly. Thus I think we both have aware of time constraints.
CielDuMatin - yes your paraphrasing is accurate! In terms of what I want (with anyone) I do not think I would cope well with being a secondary. I do not mind my partner having one or more, but I think I would need to be primary. Thus, while I don't mind continuing the shagbuddy thing for awhile, I know I couldn't do it for long.
Which brings me to ArtemisHunts' comments - yes, giving myself a limit was what I had planned. I am not sure how long it would be, but I respond well to deadlines and end points, and I know I would feel far better if I had a point in sight. The question is: do I communicate this timeline to him? Obviously it sounds like an ultimatum (which it isn't really, but it might give him the incentive needed to come to a decision. The decision being does he want to continue as shagbuddies or make some kind of committment?)
Thanks again for your advice everyone!