Incessant talking

I just wanted to ask for suggestions for dealing with a husband who talks incessantly. My husband is intelligent, reads a lot and even calls himself a compendium of useless information. He knows a lot of big words too.  My husband speaks very loud and his tone is most the time excited. Me, I have misophonia (sensitivity and even hatred of sounds, movement, etc). I enjoy the quiet, music, being laid back. What a combination. there are times I enjoy with him, like when he is relaxed and that is mostly when he is alone with me because I don't focus all the attention on him and he just is on his laptop, watching tv or we are playing a board game or even having everyday conversation. 

Here is the issue I has yesterday. We had a van full of people, 6 in total. My husband (ADHD, PTSD, and I am sure Bipolar but that is taboo for him), another woman with anxiety issues, another woman with bipolar, another woman and her 12 yr old child and myself. The ride was 1 hour and 45 minutes one way. The woman with anxiety and the woman with bipolar are Sci-Fi geeks like my husband so they chimed in and he seemed to be stoked by that and he didn't stop the WHOLE TIME. I forgot my headphones!!!!!!!!! It wouldn't be too bad if it was conversation about things everyone likes but this is Star Trek, Marvel/DC super heros (I like but don't talk about the characters as if they are real), broccoli being a hybrid, black holes, DNA, Steampunk, all sci-fi tv shows. You get the picture. There was no dead air. When we got to our destination, he shut off the car and said, "Well that was stimulating even though I did most the talking!" OMG OMG OMG, I wanted to scream "SHUT UP SHUT UP" in Steve Carrel's voice. The topics, volume, intensity of his inflection and pace was crazy! We had some laughs when I interjected with a joke or something but then he would go right back to talking. The bipolar woman got along with him well. Her husband left her last year and it seems that she was so elated to find someone right up her alley. That was nice for her. On the way back home and at the restaurant when we stopped to eat, he talked again. We saw other friends there too and one girl jokingly came to our table and said "ok, you are going to have to calm down here" since he was talking loud. He said "Hey, people have been telling me to calm down and be quiet all my life and it hasn't worked yet so...." By the time I was home at 9PM I wanted to vomit. The day started at 7AM and ended at 9PM. It was a convention too so I was sitting next to him and the whole time his leg was shaking uncontrollably, he was finishing the speaker sentences in an audible volume, just like he does at the movies, where he blurts out punchlines. It took all I had to meditate, breathe and not scream. I was fatigued, depleted and was dreaming of a quiet place in my head. I even thought of going to a bathroom stall to be alone in the quiet. My brain can actually relax when he stops talking or leaves or isn't around. When we dropped off the last person, there was a piercing silence in the car like he ran out words and no one was fanning the flame anymore. I got out of the car and went straight to bed. NO MORE WORDS were spoken and I fell asleep so fast. He went to the living room as usual to watch tv and be on his laptop. I guess I am not stimulating enough because I am over stimulated by him and I don't want to be. Mostly this happens when I am not the only person in the car. I steer him away from deep scientific conversations. Sad that we are not on the same page. I would just like to have everyday conversation and in a group setting, hear from others, instead of hearing all the same stories I have heard over the last 25 years like his horrible childhood, all the books he has read, his extensive library, mancave full of toys/action figures, his artwork, his achievments, his failures, definitiions of words as well as their origins, why the sunset has different colors, his interrupting people and correcting them as well as telling people they are wrong and telling them why. Sometimes, all I want to do is listen to music or ask other people about their life. If you ask my husband about his nationality it's an hour long about his terrible father and the abuse he suffered and then that leads to how he was bullied in school and people leave his presence depressed. If you ask him what he does for a living he will tell you how great he is at his job and then all the other accomplishments in his life. Then people ask me the same questions and I say, "I am Puerto Rican and I am an admin Assistant." End of story. 

He doesn't do well when I shoosh him in restaurants or at all because he feels like a child. I don't want to be his mother. I realize after being married 25 years that he is not going to or can not change. There are some that like his talkativeness especially is they are geeks too but most times, in fact, that lights the fire more and its like he actually gets it out of his system. I hear comments from others about how hard it is to be in a car with him. He talks a lot about his achievemenst, always has insight on an issue and is  very much an "I" man (I did this, I did that"). Once he was talking about quantum physics with a group of elderly people and a couple who are just simple and when he exited the car briefly, the sighed in relief and some said that the convo went over their head. Those moments are hard for me. My head aches, shoulders hurt, brain is fried. 

Does anyone else have this issue? If so, what can I do to protect myself? He will not take meds, will not change, can not change, can acknowledge his issues but jokes about it like saying "too bad, I talk a lot" He has no idea how much pain his talking causes me physically and frankly, it's easier to put in earplugs than to stiffle him and tell him to not talk. But then I feel rude to do that. Someone said I should drive separately but that is not conducive to togetherness in a marriage. 

I read an article today about this issue and how it can be neurological or psychological. So ADHD, Bipolar, Aspergers OR Narcissistic. I am not sure of which it is or all of them I just know how it affects me and a lot of other people except people that are just like him. This morning I looked forward to going to work to have peace. Next time, I just need to be prepared. Last year, I plugged up my ears with music but the other 5 people suffered and told me later that they couldn't deal with that all the time and had headaches. They said I deserved a medal. So sad for him because he has a reputation now and repels people but also hard for me since I am kind of stuck. 

Sorry so long but had to vent.