While you did mention in passing you were not legally married you did not mention in a clear fashion your "W" has been married to another man for over a decade.
Honestly, there is not a reason in the world for your "W" to remain married to her H and be with you and have children with you for 14 years. IMO that about says it all.
And really, why *would* your W have to do anything different. Legally, other than custody, there is not a thing you can do. Unless you had a formal common law marriage decree drawn up she is nothing more than your GF in the eyes of the law.
I have to ask... how in the world could you be comfortable living and having children with a woman for so long while she was married to somebody else?
The terms "husband and wife" are so sacred. The fact that she called you her husband while she was married to somebody else, even if only in name, is terrible!