Man, the OP's post really is eerily familiar with me. I have had the EXACT experience with an ESFP I care(d) about very much.
Basically she came on like gangbusters, especially at first, and then other times was very cold actually. What I ended up learning, is basically that she lives in the moment, entirely. When she was into me, she was very interested and did it in a big way. She followed me and sought my attention, googled my name and kept an eye out for me whenever she thought I might be near.
However, when her head was elsewhere, the opposite became true. She would have little or no interest in talking or being with me during these times. I would want to communicate and she just wasn't capable of expressing herself that way. I was like, "What did I do?"
It bothered me that rather than communicate what was bothering her, she just acted out. That never solves anything. In the end, after exchanging some words, I patched things up but we were done. After much frustration, I was reminded of the lesson, "People treat you how they are." If you have to treat someone with kid gloves, something's wrong.
Part of me wishes she could change, but the fact is she probably won't anytime soon, so it's best to just accept that. At least she's not interested in any of the 100 guys per day who hit on her so I respect that.
So, in short, my response is don't sweat it. If he is a mature person, he will make effort to connect with you. If not, screw him, he's not worth your time. Don't make the same mistake I did. You'll save yourself heartache.
That said, I mean no disrespect to any ESFPs.