Wasblind - I can't speak for all women, but the average women ain't gonna choose being alone overa good lovin' man. There is a third party in this. I don't know who or what it is. But it's there.
Dan, I'm so sad for you. But I agree with the above statement and i apologize if this seems disrespectful to you or your wife. If there is no abuse, it take a lot for a woman to leave a man she loves.
Her leaving was in the works and she's had help arranging it. This is the first step. She's thinking ahead to future without you and acting according. This should be the wake up call for you to do the same. Seek legal counsel. If you belong to a union, trade or professional organization, they can direct to to free or low cost legal assistance.
Do you know where your important documents are (wills, birth certificates, deeds, financial statements, credit/bank account numbers, SS cards, passports etc)? I bet she does. Right now you have to set aside your emotions and get your affairs in order.