Thank you for posting @PTG ,
I can definitely relate to what you are describing.
I can provide a bit of insight into what MAY be triggered in the brain of a borderline (please note this is not the same for all those diagnosed with BPD. I am writing from experience).
When a loved one spends time with their own friends, a borderline's automatic thought pattern and emotions go into overdrive. "He cares for them more than me, so wants to spend time with them", "I'm not good enough", "I'm too bad, and that's why he'd rather spend time with others" - all of which align with the BPD trait, FEAR of ABANDONMENT.
There is so much insecurity within, that a co-dependence is formed and your wife cannot live without you there all the time (or knowing where you are or what you are doing).
I remember a BPD therapist mentioning the idea of 'intense jealous'. This is not a malicious or intentional jealousy. It stems from living in a world where everything seems out of control, so they want to hang on to someone stable (for security).
I'd encourage you to have a browse through:
Topic Tuesday // Supporting loved ones living with BPD // Tuesday 25th January, 7pm-8:30pm AEDT
LIVE CHAT: BPD for Friends, Family and Carers - This Sunday 3rd October 7:00-8:30pm AEDT
Raising Awareness of BPD - Flipping the Script
This may give you more insight. Please reach out if you have any other BPD-related questions.
tyme