Op here. Sorry to resurrect an old thread, but I thought some of you might like to know what's going on with us.
After some false starts, a very close mutual friend of Lilin's and mine has expressed an interest in me (which I return, hurrah!). He's going to have dinner with Lilin and talk about how he wants to proceed on Tuesday (without me there, as he has some things he wants to hash out mano-y-mano), and then come back to me with the all-clear.
He has never done poly before, but he has all the qualities necessary--good communication skills, honesty and bluntness, an open mind--to make this work if we tread carefully. Lilin has some anxiety going forward, as his first girlfriend and best friend found each other appealing and then left him out of the loop, and he lost them both. I have reassured him that this isn't what is going to happen with us, because Best Friend and I would both rather tear our hearts out than lose him in our lives. However, since Lilin doesn't want to be monogamous with me, he DOES have to put up with the insecurities of me going forward with poly, and doesn't get to pick and choose who I date (which he knows).
I am cautiously optimistic that this will be a good experience for everybody, and if all goes well, hopefully Lilin will feel secure enough to pursue other relationships for himself--ones that are separate from me.
We've come a long way since last fall, and I think we're both proud and encouraged by our progress. Thanks to everyone on the forums who helped us when we were struggling. I'll happily keep everyone updated here if anyone has any interest.