I don't think its dumb at all.
While you're in a perfectly good relationship that has lasted for a long while, the concept about 'learning' can be pretty tempting.
It's like friends. You don't stick with the same friends because you want to learn about the world, other points of view, and how to handle people different to you. You want to search the scene so when you pick your closest friends, you know that theyre the most reliable, because you've had pretty unreliable friends, or you know that they're the most honest, because you know how an unhonest person acts. etc.
As with relationships, you want to learn more about what you want, about how you want to be treated, and how universal the way you love someone is. Even though this isn't necessarily a conscious decision, the desire to learn is a valid one.
It's not about 'am i missing out?', considering most situations, at least from friends I hear, that their intuition says so. It can lead to the wrong decision yes, but then they get what they want: a learning experience. Now they know what they want because they've now lost it and they hate it. Tragic, but its pretty standard for someone to feel like they need to know.
I thought I had it right first go. he didnt. the four next men were everything I didn't want, but I had to find that out first. The one I'm with now (for 2.5 years) is everything I want for the meantime, but who really knows later on...