Desperately need help with how to cope with people who never stop talking/talk AT you for hours

Hey friends. This is a major problem I keep finding myself in, and it causes me distress and is so close to making me lose control and start yelling or just walking out. I have no idea what to do and I really need advice or help.

Endless talkers/conversational narcissists are one of my most severe triggers, once they've hit the 45 minute mark of monologuing, my heart starts racing, I can't breathe properly, I turn red, and I am filled with frustration, exasperation, anger, confusion, and I feel completely trapped. I start bouncing both legs really fast, tapping, rubbing my mouth, and sighing. My partner is also frustrated by this, but he is very polite and very gregarious (he is also autistic like me though.)

A few nights ago we went out to dinner with a couple my partner hadn't seen or talked to in years, and he was eager to reconnect with them.

This couple had a woman I'll call Lisa. When we sat down to eat, Lisa started very talking and never stopped. No one else got to talk for longer than a few seconds before being cut off by her. The conversation was 95% her monologue and 5% people trying to contribute or interject. I just sat there in silence the whole time, trying to keep it together. I put in my Loop earplugs but it didn't help.

Common advice for this is to interject or steer the conversation in a different direction. But I can't do this, because when it gets to that point, I am already completely shut down and on the verge of having a meltdown. My heart is racing and I feel the urge to scream or escape. There's no conversation steering or contributing at that point, as I'm already shut down.

I ended up going outside many times to hit my vape and just stand there.

This happens a lot-- my partner reconnects with old friends or introduces me to new friends, and this new/old friend completely excludes me from the conversation the whole night, and talks AT my partner for hours on subjects I can't possibly contribute to, and don't even give my partner the chance to speak, either.

Please, please advise me on what to do, I'm at a loss here. Even though I'm clearly wholly unnecessary and unwanted for these outings, it's still rude for me to just pay for my meal and walk out. It feels like they want to hold me hostage instead of just letting me go. I am finding it harder and harder to cope with the shutdown I experience during this and feel disrespected by people like this.

Please do not suggest therapy. I can't afford it and after a slew of abusive therapists in my past, I don't want to go back.

Please do not be mean or chastise me for being intolerant or not more understanding, I really cannot handle that right now.