i like cindies idea of a probation period of sorts.... its a great idea.
reality though sometimes rears its ugly head. i dont know you well enough yet julia, to know if you can compartmentalize your feelings like that. I myself have the benefit of being able to redirect feelings back toward my primary (gemzi13), and allow things to develop slowly toward a love interest, or even quell a large portion of heartache... i dont know... its kind of weird. however some people cant, gemzi has this challenge, her heart is all in before you know it, that just how she is. (very very loving)
it seems you are already exercising my first piece of advice.... which would be:
1st.: use your mind and your heart at the same time. the mind tends to be smarter, but the heart is so much louder.
b.: i think a sit down with his primary is in order as you mentioned, for a talk. the problem i foresee is that she was involved in the initial heartache. she was not alone. and the question arises.... did his primary see a trend in him that scared her, did he handle nre in such a way that did not make her feel like a third wheel, unwanted, or like she was losing him?
number 3: whiplash hurts for a long time, be sure to pick up a neck brace at the pharmacy.
i wish you the best of luck with this, as always try to keep and open mind and heart, but let the mind do the talking, and be as objective as possible. never know what a sit down discussion will reveal if all parties are open and honest, tempered with compassion.