Well I got very confused on the time data, but I am assuming you have been over everything that could be discussed about the M, about boundaries, and especially about OM. Am I right? If so, why would this next time be different?
You said she reached out toward you in Oct. Was that after you started dating? Then she got kind of ugly about your GF in Nov?
IMHO, it would be a very long-shot that a reconciliation will come just yet. She is still seeing OM, as you pointed out...and now you have GF's feelings to consider. I personally am wondering if your W isn't feeling a big case of jealousy and wants to prove that she can still win your heart over that of another woman. She doesn't want to drop her OM, but she doesn't want OW to have you, either.
I think it would be unwise to "date" your W as long as she is obviously connected with OM. But, that's just me. I never could ride the merry-go-round without getting sick.
If you continue to GAL and let her be....then she may be ready to make some much needed decisions before playing games....and I can't help but believe that this is all it would be right now.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!