If she is a Christian, she needs to repent. Most will not. The first counseling session will tell you clearly where this is going to go. A person never "falls out of" love, since love is a decision one makes in the first place.
She has either been using you for all these years to simply get what she wants, or else someone else is buttering her bread now. Most likely both. Women do not go to the extremes that you are describing simply due to a mid-life boredom crisis. Either way, it's her problem.
Her girlfriends are your enemies now.
GET A LAWYER! Even a bad one is better than going it alone.
