A lot of people post about not being able to go out with friends because their pwBPD gets so angry and jealous of them being out of the house. I used to have the EXACT same thing happen and I was really isolated and alone. It was through my isolation that my H was able to gaslight me, convince me that I was the problem, and control my life.
Once we got into a church, I began to attend women's groups and met a really close knit group of ladies that I spend time with at least once every couple of weeks. It wasn't an easy place to get to because my H saw them as a threat, but this site and the tools of validation and
DEARMAN really helped me begin working on loosening the chain he had on me. Many times he even painted my friends black. One of them it took almost 2 months for him to like her again. Another he is just getting over being angry at her because of my most recent dysegulation from him.
So I've known for a month that my friends wanted to get together for a birthday dinner. I also know that if I mention it too early, my H will forget or he will stress over it. I usually wait until about a week away from the event (this time I waited a little closer to the date because he was dysregulating on Monday and Tuesday).
I like to introduce the subject through text first. For me it works better, but other pwBPD may have difficulty with text. During the late morning and early afternoon his moods tend to be better. He is also focused at work so he is less emotional. Also, I still get really nervous about tell him of events so through text he can't see my nervousness. I don't want him to interpret my nervous as hiding something. So here is what I said:
Me: Sunday evening the girls want to meet for (friend's) birthday at Cheddars or Olive Garden. I know SUnday's are not the best day but would you care if I go? I'll get home around 8:30 and we can stay up later so we can still spend the evening together.
Him: Ok
Me: Thanks. I can bring you buffalo chicken strips if we go to cheddars.

Him: Yes! Or the gorgonzola steak thing at Olive Garden
Me: mmmm. that's good.
Couple things I did here:
1. By asking if he cares if I go, I allow him to have some say in things. For events that are not optional to him, I change the wording a little.
2. I gave him as much detail as I know, places, times, etc. These details help him know that I'm not trying to sneak around
3. I acknowledged that Sunday's are stressful to him because he feels like the weekend is ending so that means ours time together is ending. (Validating)
4. I let him know that spending time with him was still important to me. (Validating)
5. I throw in the extra treat of food because... .well, food. And he loves buffalo chicken strips so it's an extra bonus. (Kind of a way of rewarding good behavior ) This also lets him know that I'll be thinking of him while I am out with friends.
And whola! He not only is ok with me going out. He is excited for me to go out because he gets food!
What do you guys think? Is this something you think might work for you?