Welcome buttondaisy!
You are not alone!
It strikes me how how much you have given this man at the sacrafice of your own well being.
I dont know what happened when you talked about 'falling down a plughole' but you got out of it (good for you!!!) Dont let him drag you down there again! You need to take care of YOURSELF!
Im sorry but he does not sound ready to get help. And you dont sound ready to let go. But thats ok! Because joining here is one step in moving forward -FOR YOU!!!
I am pretty new here too but SR has been so helpful and supportive AND non-judgemenatl to me already. Yes I have supportive family and friends IRL, but when I come here, I feel such peace, because the UNDERSTANDING and genuine concern just emanate from the screen!
You will find people on here who have been through/going through everything you are describing. YOU ARE NOT ALONE! (((((hugs))))