That is very intense. I can imagine the burden and fear that comes with wondering if this time he is serious.
Do you have any close friends you could share with? A counselor?
What activities do you do for yourself? Finding ways to relieve your stress through things you enjoy will help you immensely, especially if it's something you enjoy so much that you can forget about your home troubles for awhile.
I used to run homes for people with developmental disabilities. I found myself in a very stressful environment in handling behavioral issues at work and at home. My line of work had a lot of turnover and staffing issues. I would take a little bit of time for myself after work each day, maybe 15 minutes or so, to find somewhere quiet to just sit in my car and take a break. I would read, pray, cry, etc. Whatever it was I needed for myself for the day, I would take the time to do it.
We had a term for what it sounds like you may be experiencing. It's called secondary traumatic stress aka "compassion fatigue". People who are frequently exposed to other people's trauma experience this type of trauma. I'm not sure if this is something you may be experiencing, but if you think that could be the case, here is some information on it:
www.nctsnet.org/nctsn_assets/pdfs/CWT3_SHO_STS.pdf