I disagree. If someone forces you to do something that you don't want to do - then they don't care about. If someone tries to make you do something that you don't want to do but that they want you to enjoy, their motives are less clear. Many parents make children do things that they don't want to do, that's how we grow as people. Many children are forced to play the piano or have maths tutoring or join clubs they don't want to be part of. This isn't because their parents don't care. This is too simplistic for human psychology.
In this instance, your boyfriend may have been trying to share something about his life that he thought you might like - you did not. That doesn't mean he doesn't care about you - nor does it mean that you're a prude. Consider the reverse, if you ever asked him to stay in and play video games with you when he'd prefer not to, does that mean you don't care about him? Or does it mean that you want to share something with him?
Other comments on this thread are particularly denigrating to Max, which may be the point of the article, but the takeaway is simple. You're an adult. You have boundaries and you should be clear about them - they weren't clearly defined because you got out of the car and went to the party. Atttending the party was tacit consent. Getting out of the car was tacit consent. Yes... perhaps you were pressured by Max - but you are still an adult and still responsibile for your actions and it is important to understand that you were not forced and you're not a child. You cannot infantilise yourself out of responsiblity here and lay the blame squarely with Max.
It's easy to blame Max, the harder question to answer is why you went to the party at all once it became clear what it was. Once you were there and you encountered Manson in the garden you understood your boundaries, you clearly defined them and you left the party. You weren't in any danger, just socially uncomfortable and didn't enjoy yourself. Max may have been wrong to take you, but who knows.... perhaps that anxiety/arousal moment in your story could've gone another way. Perhaps in a different universe we'd be reading a story about how you discovered your secret swinging kink side and this would be an article about female sexual empowerment. Who knows?
Max was wrong to have called you prudish, but that's an equal and opposite judgment to the one being made by people who use terms like 'debauchery' to talk about sexual practices they don't engage in - consenting adults can do what they like with whomever they like. That's how a liberal society works. Likewise not participating in swinging doesn't make you prudish. That's pure groupthink.
So whilst I enjoyed your article and the excellent storytelling you've done and I agree that standing your ground when bounaries are pushed is a good thing - I disagree with your conclusion. If someone tries to make you do something you don't want to do - it doesn't necessarily mean they don't care much about you, they may care about you a lot. However, it should definitely warrant further conversation and more clearly asserted boundaries.