I’ll echo the PPs. If what you’re saying about J is all 100% true, with no exaggerations, he is absolutely, without a doubt, abusing you. Sexually and emotionally.
I’m going to completely disregard C and the cheating for the purposes of the advice I’m about to give. (By saying I’m disregarding it, I’m not saying it is justified because of J’s abuse. I’m just saying it has no relevance to what you need to do next. Getting out of the relationship with J would be necessary even if you hadn’t cheated.)
OK, so here’s my personal opinion on what your next steps should be. Get all of your shit in order. You said you already sat down and crunched the numbers in terms of finances, and that’s a good place to start. Make sure you have all of your money in your own account, which J has no access to. Figure out anything physical/material that is legally yours, and write it down. Make sure you know where all of your important documents are located and that you have immediate access to them – birth certificate, social security card, passport, etc. Then, talk to someone IRL that you think you can trust. Tell that person that you may need their help/support in the near future. Set up a place where you can stay if you do have to leave without warning, or even a place you can stay if you have a planned time to leave but just can’t find or afford anything else before you move out. After you do that, find a counselor and schedule an appointment. Having that appointment in place, whether it be before or after you leave J, will be immensely helpful.
Finally, when you talk to J, I think you should definitely leave out any information about C and your indiscretion. I know you said he isn’t violent, but why make him angry (or angrier) if it isn’t absolutely necessary? And, don’t even bother telling him that you’re unhappy and want to leave because he “does this and this and this.” Unless you want to try and work on the relationship, then telling him exactly why you’re leaving won’t make a difference. And, as a master manipulator, he may be able to use what you say about him, twist it around, blame you, convince you to stay, etc. Don’t even give him that ammunition. Just stay strong and keep repeating that you’re sorry, you rushed into the relationship and marriage to young, and you are unhappy and want out. That’s it. Just keep telling him that. And then leave.
I know you say your parents absolutely love him, and here’s the thing. Emotionally abusive people and manipulators have this sort of charisma for the people they aren’t abusing. They know exactly how to act and what to say to come off as charming and wonderful. I feel very certain that if you were to relay to your parents what you’ve told us, leaving out the cheating part, they’d be GLAD to have J out of your life. So please don’t worry about being judged by others.
This is a terrible, messy, unhappy situation all-around, but it’s not the end of the world. It’ll suck while you’re going through it, but you have no other choice, unless you want to continue being abused for the rest of your life. The sooner you take control, the sooner you’ll start getting your life back on track. You are young. This whole debacle will recede into ancient history eventually, and by that point, you’ll have re-established yourself and you’ll be happy and look back and think “Man, that sucked, but I learned a lot about myself and things are great now.”
Best of luck.