Bayliss,
I do think you need to move, no question. You need to put distance between the person who is triggering you. Also the living situation doesn't seem ideal to me. When you come home you need to relax. Your boyfriend's mum could find some other tenants to help pay the rent.
I have a family member who triggers me, the other day I really felt like a drink after an encounter. I certainly could not live with him. I am now being more mindful of my boundaries and what I can cope with. Yesterday we all went out to lunch it was great but I am going to keep distance for awhile.
Bayliss your sobriety is paramount.
All the best
CaiHong