They have a commitment to us, they are socially and morally bound to certain constructs and yet they are moving on. this often brings them great cognitive disconance and internal conflict as they atempt to balance their need for supply with their need to maintain their false image.this brings on quilt and anger and frustration. hence the nasty phase. Additionally their superior stance once we are devalued brings contempt toward us.once they overcome the above conflicts within themselves, they detatch. Yes, I believe pds can detatch also. this is so they can reimagine themselves within the new constructs. ie a cheater, or a divorsee, or...... often on this board we read where they project these things onto the non, by becoming the victim or insisting the non is cheating, or needs therapy and gaslighting the non. Once they are over the damage to image and have reinvented themselves so to speak, they engage the new supply sources and we as nons mean little to them. Once replaced they often do not even need the supply from negative interactions, so abuse may subside.I think they stay if it benifits them. Especially if we let them have their cake and eat it too.I have read in many threads here about pds leaving or getting divorsed and its like they turned a light switch. its simply over for them and they have a new partner immediately, or at least have little remorse or dont grieve the relationship past that point. its simply done for them when they aquire the new source, and complete the devaluation.
The hard thing is, that many are high functioning, and other people outside of the relationship see a healthy, hard working person, who is responsible and SURELY wouldn't act so horribly or dysfunctional within their relationship and home! They can be practically responsible with children, work, paying bills etc, but when it comes to emotional maturity they are destructive. They lack the skills to be able to deal with certain thoughts and feelings in a mature way. And unfortunately, they often believe that there is absolutely nothing wrong with them because they can hold down a job, look after kids, or the house.