Hi debyt,
what you asked is sensible from your point of view. In terminology of this board these are however not real boundaries - as you noticed they seem not fully under your control.
The challenge for you is that he seems to be very, very frightened of abandonment. It may be something to validate, we often shy away from validating these negative emotions - partly since we share them. Validation alone probably won't let you overcome his fears as fear of abandonment is a very strong fear at the core of BPD. For him your plan is a plot to leave him. The question is less whether it is fair as to how to do it without him going through major panic attacks and melting down. I don't see him moving out unless you force him. All points to very strong attachment of him to you (not moving out, touching, diary invasion).
Two options for moving out:
- Boundaries - force him out somehow. This is likely going to be a bigger drama.
- Managed therapeutic separation that somehow takes also care of his abandonment fears:
https://bpdfamily.com/message_board/index.php?topic=141686.0 . Possibly when DBT starts with the help from there?
short of that:
- Working on boundaries while he is man caving. You have to be strict of some things and not let him push you over. Boundaries are not really about fairness but what you deem necessary for you and for what you are willing to make a stand.
Can not being in the same house be more damaging regarding his love languages than staying and enforcing these boundaries?
Restoration of respect is in my eyes a required first step before love language / intimacy can work well. Boundaries are easier to establish when there is some physical distance. Whether cave land is far enough only you two know. Since he has a history of invading privacy I might consider locks on whatever inner or outer doors a useful thing.