They will idealize you until you 'submit', when they feel that you are 100% in the relationship - THAT is the point when abandonment fear reaches its peak.
Well, if someone is primarily a borderline, that is the point when fear of engulfment reaches its peak; a borderline's continual focus, unconsciously, is to balance the opposing fears of abandonment and engulfment and straddle the fence between them, which is always moving. Now if someone is primarily narcissistic, it's about chasing narcissistic supply, and once the relationship is established and the borderline/narcissist is no longer considered the most amazing person in the universe by their partner, the narcissistic supply dries up, so off they go in search of new supply.
I found this many times after spending the night with my ex. Basically in the evening she would be on her best behavior, even asking several times if I was staying. She could not stand to be alone and needed to be cuddled and held for long moments. This would lead to making love.
In the morning, she would become a different person. Having achieved having someone their to sooth her for the night, she defended against intimacy, by becoming argumentative, sometimes if dismissive of whatever I had to say. She would find faults with me. I didn't hold her long enough, or I fell asleep to quickly after, or I didn't let her get a good nights sleep. All these things would confuse me. Makes sense in terms of fear of abandonment/intimacy.
Dude, my ex was so afraid of real intemacy she would tell me from the beginning that sex doesn't have any deeper meaning for her. After sex she used to say "thank you". Really? "thank you?" That's messed up!
