It is hard, and you do need to stand up for yourself. Gentle but clear boundaries can help everyone through the process.
If someone is being accusatory at every boundary or facial expression... it would make sense to feel hurt and confused by an intense reaction from him. Especially if you meant no harm.
It seems like he takes things pretty personally. His behavior suggests he probably feels really insecure in the relationship.
Let me try to explain by switching places in the example you gave.
If I am in a secure place where I confidently trust people I'm with, and my husband was to joke about the good side of being divorced with another woman, I would probably take it as a joke, and not take it as a sign they don't want to be married.
But if I was super stressed, struggling to trust, and already feeling disrespected (even if this is not deserved) and my husband was to joke with another woman about how great it must be to be divorced, I'd probably feel even more insecure about the marriage.
I hope that I would sit down with my spouse and have a productive conversation about how I'm feeling and how to restore a sense of security and trust in the relationship.
Instead, in your case, he just threw a passive aggressive fit over it: Which probably led to you feeling more frustrated, your pulling away more, his feeling more insecure, and him lashing out more, and you pulling away more... and around and around the cycle is goong.
Handling conflict and insecurities and fears in the begining of a marriage is super hard work even without the added weight of PTSD in the mix.
You may both need the guidance and coaching of a couples counselor to step in and help you both communicate better through these rough spots and so that his insecurities don't continue to be self fulfilling prophesies as he lashes out.
He may also be coaching on how to set boundaries himself - not because you are doing something wrong. Lashing out is a way of setting a boundary and communicating needs - a really unproductive and unhealthy way. He may need help figuring out a better way of doing it and to mange his fear of being vulnerable enough to handle healthier ways of communicating. Individual counseling is great, but couples counseling (with a very trauma informed couples counselor) can give a lot of feedback and in the moment coaching.
If you do set stronger boundaries with his tendency to lash out, expect it to get worse at first. Don't get discouraged though if that happens. That's pretty normal for it to get worse at first. Ranting at you is in a way or avoiding of dealing with himself and his pain. If he lashes out then he doesn't have to do the hard work of resolving conflict effectively and then having to confront his own pain and insecurities and fear.
Don't give up, and keep reachinh out for support for you.
Do continue to try to understand. It will help to figure out what is really happening and how to respond to keep your sanity through it.
It is also true that you won't always understand what's happening or why. I have PTSD, and I have been learning about it for well over a decade. I support someone with it as well, and even as a sufferer, I still am sometimes confused or baffled by a certain reaction.
When in doubt, try to be as steady and safe as possible. If you need to step back to not react to his reacting, then that's ok, even good. Try to tell him you are taking space before you do, and tell him how you will do that, and when you plan to reconnect. That will hopefully help his insecurity not flare up quite as bad. For example, if you can't continue to take his calls, that's totally ok. Tell him something like, "I won't be able to talk to you right now because I have to take care of myself. I am able to talk to you in two hours." Or however long you need to regroup. He may still lash out and feel disrespected, but over time, he may also learn that taking care of you isn't grounds to freak out. It means you are working to stay in the relationship, not abandon him.
He will also hopefully get much better at managing his symptoms and fears himself and not push you away so much.