<human>: Condense the text into a few key points

Yes I know, I'm 20. I'm young and admittedly stupid. But I've started noticing a pattern with my relationships. I haven't even had that many relationships. I've slept with five people in my life, and had an exclusive, "boyfriend-girlfriend" type of relationship with three of those women. 

The pattern that keeps happening is that after a month or two go by, and I inevitably get bored, for lack of a better word, with my relationship. I start to wonder how the relationship would be with someone else. How much better it could be. I become despondent and introverted. I have a hard time talking about these feelings with my partners because I feel like it would really hurt them to say that I've been thinking about a new relationship.

The most troublesome thing to me is that it's not even a specific thing or person that starts to spark these feelings. it's not like I see an attractive girl at the gym or on campus and immediately start fantasizing about her. Instead, I'm fantasizing about some sort of ideal partner that's entirely in my head. It's no specific person, just a collection of idea about how the perfect girl and all the fun things we'd do together that for whatever reason me and my current girlfriend aren't doing. And it's not crazy impossible things like exploring the world, it's stupid inside jokes that me and this imaginary partner would have. Little minutia like that is what I imagine.

I worry that this "dream girl" of mine is too good to be true. I don't know if I believe soul mates exist but in my imagination they do I'm afraid that if I keep having these thoughts I'll never settle down with someone in real life because I'll always be searching for THE One. 

I don't know if I should keep moving from relationship to relationship until  I finally feel whatever "it" is that I'm looking for or if when I start having these sorts of thoughts I should try to make it work with the person I'm actually with.
<bot>: Whenever I get into a relationship, I inevitably start to wonder if the things could be better with someone else. I'm scared it'll always be like this and I'll never find The One.