Over 20+ years, I have seen a whole gaumut of people on the sexuality spectrum.
It seems to me that your W is exploring new avenues in the sexual realm and is experiencing a whole set of emotions that are all new to her. Not to be crude here...it is a lot like someone buying a brand new car with heated leather seats, digital music, built-in phone, humming quiet engine, cool compartments, etc.
Doesn't necessarily mean that your W will transition to being a fully lesbian just because she "says so". I was dismayed to read that the folks on the lesbian site is giving your W pointers on informing people about her "coming out" process without fully understanding her marital history with you and her daughters. They don't know what they're dealing with at all and shame on them for doing it.
You're going have to dig deep for patience while your W is off exploring over thar younder.
Just be strong for your daughters and continue being you. If your W brought up legitmate complaints about you and the M, then do 180's that are permanent for YOUR own benefit because you'll live with them regardless if W comes back or not.
