(22F) How do I break up with my boyfriend (24M) when he thinks everything is fine?

I’m a woman in my early 20s and I’ve been with my boyfriend for a couple of years. This is the first serious relationship for both of us.

Ever since we started dating, I’ve felt like something was missing, and I think that thing is connection. One of the biggest issues is that we barely talk. I don't mean we avoid each other or argue. I mean he genuinely seems to have very little to say most of the time. Restaurant dates have always felt awkward because I carry almost every conversation, and phone calls are the same. If I stop asking questions or bringing up topics, the conversation usually dies.

For a long time I convinced myself this was normal because this is my first relationship. But when I look at other couples, they seem genuinely interested in each other's thoughts. They tell stories, discuss ideas, joke around, gossip, and actually enjoy talking to each other. I don't feel that in my relationship.
We've also always had very different needs regarding affection and intimacy. His interest in it is so low that I've genuinely wondered whether there might be an underlying issue contributing to it. Whenever I've tried to bring up how it makes me feel, though, the conversation tends to become about me wanting "too much" rather than us trying to understand each other.

Something else that bothers me is how different I feel around him compared to everyone else in my life. Around my friends and family I feel funny, confident, intelligent, and interesting. Around him, I often feel invisible. Sometimes I wonder if it's because he doesn't seem particularly curious about me as a person.

Lately I've realized I've been suppressing these feelings for a long time. The relationship was never bad enough for me to leave, but it was never good enough for me to feel truly fulfilled either. Looking back, I think I've stayed because it's comfortable and familiar, not because I'm genuinely happy.

The thing is, I've already made my decision. I know I want to end the relationship. We're currently long distance because of work, so it would have to happen over the phone, and he has absolutely no idea this is coming. As far as he knows, everything is normal.
How do you break up with someone when there isn't one dramatic reason? How do you explain that after a couple of years together you've realized you're fundamentally unhappy and disconnected, without turning the conversation into a debate about whether things can be fixed?
Has anyone been in a similar situation? If so, how did you start the conversation?