I'm very sorry that you are going through this.

I'm bipolar and in a serious relationship with a non-mentally ill man. He's had a pretty simple life, so how he knows how to handle me is beyond my comprehension, but I'm happy for it!
This is what works for us: Our defense against major episodes is to prevent rather than deescalate. We let everyone close to us know of my condition, and the warning signs of an episode, so the pressure isn't entirely on him. Everyone's warning signs are different, so as Sesiley said, making a trigger list together is a great idea.
I take my mood stabilizer every single night, no other option. We have gone through the best way to prevent an episode from forming, and agreed on terms that are reasonable for me to take my as needed antipsychotic or anti-anxiety. I limit caffeine and alcohol, and stick to about 8 hours of sleep, and if I am showing any symptoms, then we know those guidelines have to become even more strict.

When I am enraged about something, what helps me is feeling that I have someone on my side. Sometimes if my boyfriend agrees with me rather than tries to rationalize with me, I simmer down a lot faster. It's an unorthodox approach, but it works for us. Another approach we use is having designated destruction. It feels good to release anger. For example, taking up cardio kick boxing or playing Grand Theft Auto or throwing things in a controlled environment has all calmed me down to feeling human again.

Hopefully any of this information is useful. I am sending good thoughts your way.