I'm going to give you the benefit of the doubt and assume you aren't trolling. Even if you are, I hope someone else may find this advice useful.

So, I understand that you feel betrayed that your boyfriend did something peculiar and interesting without involving you. Is that about right?

If that's the case, can I gently suggest a few things?

First, clearly communicating your expectations is the best way to ensure that they'll be met. From what I've read of your comments, it doesn't sound like you explicitly expressed to your boyfriend that you wanted to be part of his Storm Crow-eating adventure. It really would be nice if our romantic partners intuitively understood what we wanted without our needing to say it, but that isn't a realistic expectation.

When someone you care about does something that hurts you, that absolutely sucks, and it hurts more to realize that they had no idea it would hurt you, because you didn't make your needs met. If you didn't communicate your expectations, then much of the responsibility here is on you. That is not a fun realization, and many of us, when faced with that responsibility, will try to wiggle out of it, insisting that "they should have known!" instead of accepting that we could have done better. I hope you can find it within yourself to both accept the responsibility for not informing your boyfriend of your expectations and forgive yourself.

Second, are your expectations reasonable? If you expect that your partner will involve you in all of the peculiar and interesting things they do, and your reaction to not having your expectations met is deep hurt and public breakups on Reddit, then to avoid that level of pain, perhaps it would be worthwhile to examine if your expectations are actually reasonable, and modify them if they're not. Personally, I don't think those are reasonable expectations, and I expect that if you hold onto them, you're going to continue to feel hurt and betrayed, because nobody can involve their partner in everything like that. But that's my own assessment; you get to conduct your own.

Another thing worth considering here is what do these expectations mean to you? What do they do for you? For instance, does it make you feel special to be involved in your partner's fun adventures? Do you want to participate in what your partner does because you're uncomfortable with them having significant experiences that don't involve you? Knowing that about yourself will allow you to make better-informed decisions about your own behavior, including the boundaries you set and the types of relationships you seek.

Once again, I'm sorry you feel so hurt and betrayed here. I think you are handling it a bit clumsily, and I hope you can learn from this to have more successful relationships in the future.