Hi and welcome!

I'm sorry to hear of your struggles. the Dr. Jekyll (loving, generous, adoring) person keeps us involved - despite the Dr. Hyde (vile, vicious, hateful, threatening) person that emerges.
I'm in 25 years now and have come to accept that I can't continue any longer. My life, too, has value and it can't be all about just living to "appease" and "temper" my BPD spouse. The abuse has drained me and so after many many years, I'm working on detatching.
Every situation (though similar in this way: Jekyll/Hyde) is different. Some people elect that they will suffer the "bad" so they can keep the "good." Other people, though, the scales are simply too imbalanced and the "good" cannot overcome the "bad" parts.
So, I'd say - come here! Vent - learn - and share. That helps! You're definintely not alone in what you're feeling and all the insecurities and confusion about what to do.
There's some great books out there "Stop walking on eggshells" for instance. Watch videos about BPD, learn the "jargon" involved and educate yourself.
Knowledge is power and it can help you determine whether you feel like your situation is one in which you're willing to cope with, or if you feel like you don't want to live your life - for someone else's distorted behaviors.
It's not an easy place to be, love. But - you're not alone!
So - yeah - come here, read, educate yourself, browse the web, learn about this disorder and the effects of being in a relationship with someone who has it.
And lastly - get yourself a therapist! I can't say enough how much help they can be! They can help you see things from alternate perspectives, gain insight into both your spouse and yourself, teach you techniques for coping with the back-and-forth, and also validate your own life/feelings.
I hope you'll post again soon and hang in there!

~Gemmie