I was going to post on my thread, but decided my employer deserved more of my time because that could take two hours. However, I decided to stop by and see what's up with you and there certainly has been a lot of activity in your neighborhood.
First, I must add that you are doing a great job in trying to understand S and how your actions influence him. As Betsey noted, however, you also need to understand YOU.
I won't lecture again on maritial versus non-marital commitment (I should use this as an automatic insert on yours on H2H's thread), but will remind you that I believe this is a critical distinction even if M and non-M R's have similar dynamics at various levels.
Within this framework, it occurred to me that significant open questions remain about S's goals and needs in his R with you and I wonder if you (or S for that matter) truly understand what they are. For example, if a T were to sit down with S and ask him: "What are your plans with Jennifer and how do you hope to achieve them," what would S say? Would his answers be different if he said 1) he wanted to marry you and live happily ever after; 2) he thinks about marrying you but is not sure; or 3) he just enjoys the R for what it is now and he'll take it from there one step at a time.
With this, maybe you can see the distinction with plans and action steps in general committed Rs versus married Rs. For instance, if he planned to marry you, S's plans would focus not only on his needs, but how to make you happy for the rest of your life and truly melding his needs with yours. On the other hand, if he was just thinking about it--the plans would not only consider the items above, but also what actions he might take to convince you that he was Mr. Right (your actions may already suggest to him that you've already made up his mind and he can skip the hard work entailed in this part). It would also include the slow dance of convincing himself that you were Mrs. Right--a place that involves all the testing you noted above. It could also include a test with no end where external circumstances compel him to make a decision. Finally, if it's still just a regular R with no clear destination, the plan may simply be to do whatever works for him right now--which requires accommodating your needs at times, but may only be relevant to the extent it ultimately satisfies his needs alone.
IMHO, his goals necessarily influence your goals and actions in your R with him. Right now, you seem to be trying to get your arms around a big blob of jello, but within the mold you have selected. It has some shape and offers delicious rewards, but still is very hard to grasp.
Only you can decide whether or how far to force these issues, but the questions remains: Where is S and what does HE want?