THe is in DBT therapy and a mandatory DV therapy. I work on my part daily, but have started to notice myself getting frustrated more lately. Yes, things are better since he isn’t yelling at me or the kids, but the hard part is the crazy judgment is still there and coming oit is strange ways.
Here's the thing- a relationship is between two people who love each other and want a life together. He's doing some work and you are seeing positive changes, which is all you could hope for. My kid is BPD/bipolar as well and suspect the same for my ex- when they're happy, they're SOOOO happy and fun to be around. The downside is reckless thinking...'let's jump over the couch to make the kids laugh' sort of thing...only to shatter the glass coffee table in the process.
You have a part to play as well and it might not be as abundantly clear since he won't verbalize it (because he literally can't). First and foremost, he needs a partner that's on his side and supports him...and of course you do that. Saying that to him though goes a vey long way in letting him know that the recent changes are welcome and you appreciate his hard work in therapy.
The other side of that is boundaries, which are for you.
Boundaries are an easy thing to get wrong in the mental health world because we want to say, "Stop leaving the toilet seat up or else!" And maybe we say that in a completely different way, but that's ultimately what the BPD in our lives hears regardless. It comes off as a confrontational challenge that only makes things worse.
The right way to enforce healthy boundaries is when he crosses a line, speak about it directly and lay out the options. For example, if he starts ranting and yelling, you could reply softly, calmly and say, "We've both had a tough day and I don't want to argue. I'm going to go grab a drink and we can talk this out in a few minutes."
This lets him calm down, it lets you refocus, and maybe the argument can be avoided.
But here's the other thing it does. Every time he starts getting loud, you're telling him in a kind, non-confrontational way that you're stepping away for a few minutes. And if it escalates, then maybe you bring the kids for ice cream or to visit grandma...that sort of thing.
But whatever you do, you're making it known that he's fully in control- calm down, take a breath, and we'll talk. Keep it up and I'm walking away because that's what is best for both of us right now. It's him choosing every time, and you let him make that choice.
When it comes to odd looks and snide laughs, you need to decide if it's enough to make a boundary over. For me, I'd just let it go, but sometimes it might not be possible. It's something we'll always have to work though as we pick our battles and figure out how to express that they're acting like a child, yet we still love and support them.
I hope that helps!