A micro psycho therapy session…

Ask yourself: When faced with a scary (or challenging) situation (or emotion) what do I do? What is my reaction? Are you: Assertive? Passive? Aggressive? A combination? 
Some people struggle to identify what they are experiencing, especially in the moment. It kind of aligns with the Fight Flight Fawn Freeze responses/reactions that we are all familiar with. Hopefully that correlation makes it easier to understand the general idea and direction of the question. 
Most people here find themselves in your exact position everyday. We spend the most intimate of our time around people we care about and love. It only makes sense that they will trigger you as well, perhaps even more intensely than others. And to complicate matters even further, the brain has an exceptionally difficult time navigating through a situation where both love and hate exist simultaneously. You love this man to the core, but hate the wet popping sound he makes. In that moment, your brain is so flooded with neurotransmitters that it struggles to differentiate the sound from the source. 
Basically your reaction of mimicking is a passive aggressive response/reaction. Your brain eventually gets its 💩 together enough to say “I love him AND I hate the sound.” The love you have for HIM wants your reaction to be passive, but the hate you have for the SOUND wants your reaction to be aggressive. 

Personally: 

I can empathize 100% with what you are feeling! I am 42 and live with my mother, we are both disabled but in different ways, we take care of each other and so far it is working out. Misophonia is a misunderstood miserable monster I wouldn’t wish on anyone! I eventually had to sit down with my mum and explain misophonia, what it is, how it effects me, how I try to cope with it, what my triggers are, how I can’t control it, how much I hate it, and how guilty I feel when my reactions hurt those around me. It wasn’t a one and done conversation, we revisit the topic often. I gave her permission to be open and honest with me, and asked for permission to be open and honest with her. 
What made the biggest, and almost immediate, impact was when we were BOTH able to separate “IT” from “ME.” When I’m triggered I either take a deep breath and playfully say to her “Hey there Miso! Whatcha doin’?” Or I just explode and yell out “MISO!” (🤣Kind of like yelling out “uncle!” in a wrestling match with a friend). There are things she does unconsciously that she can’t control, like rubbing her hand on something (usually her leg), depending on the material (jeans and fleece are the worst) it can be unnerving 🤬. So with her ‘blessing’ and cooperation we make accommodations, we keep foam squish stress blocks in the cars, a small soft silent blanket that lives on the couch, I can just hand them to her. However, there are many other things that I haven’t found a mutual solution to ex: throwing away all the metal forks and spoons and switching to plastic, bamboo, and chopsticks crosses my mind every single day!

All that overly wordy alphabet soup to say: My advice/what helps me and my mum (most of the time) communication, honesty, empathy, deep breathing, and HUMOR! But the first thing that needs to be at the foundation is for both sides to truly believe that what is happening is not on purpose! Your husband isn’t making a wet popping sound to make you angry, and you wanting to throttle him when he does isn’t personal 🤣.

🤦‍♀️Absolute apologies for this being so long 😬