Definitely read "Splitting" and also read up on BIFF communication.
You're fortunate that there are no kids involved, so just keep that in mind: You can and will eventually extricate yourself from this situation...
A few suggestions:
- get a voice recorder, and keep it running 24/7. even if you're in a two-party state, keep it running. it's the only thing that will protect you from false claims re: DV, etc.
- if your w is prone to rages, violent behavior, or self harm, consider installing security cameras. again, it's the only way to protect yourself when/if a false victim narrative attempts to frame you for her injuries, etc.
- make sure anything valuable to you is already secure before you deliver the news. remove any important papers, heirlooms, etc. to somewhere safe. I put a couple of file boxes of things in my uncle's basement, including harddrive backups when I went through this. I was concerned that my ex would smash the computer, etc.
- the recommendation to have your atty deliver the news is a good one.
- have contingency plans. i.e., if you intend to cohabitate, have a backup plan in case that doesn't work out.
- be ready to call 911 if your W threatens self harm or behaves in a way that's dangerous to others. candidly, this may be the only way that her erratic behavior can be documented. there's also a small chance that such intervention will actually help her in the long run. too often, those of us in caretaker roles are reluctant to take this action and sacrifice ourselves before we put a partner in a position to face consequences. my strongest advice is: be ready to make that 911 call if there is a real threat or danger, and let your W face the consequences.
This is truly a huge topic, so don't hesitate to check in here anytime with more Qs, and let us know how you're doing.