Adding to what Maestro said: In my experience, as you get older, and you experience other personalities on a larger scale; when looking back at that one person you sort of realize that there are these underlying qualities about their personality that you realize weren't all that attractive to begin with. You may not even be fully aware of why, but you know you don't feel that near-obsessive draw towards that person. That's definitely a relief in my book. The only thing you have to forgive yourself for is the time you can't get back investing into that someone. Who really cares though since it's all a learning experience in the end.
True, I've pretty much ended up losing all attraction towards all of my exes, regardless of who ended the relationship. Doesn't stop me from my current hopeless romantic obsession, though :/
But it wasn't even when I was talking to him, but afterwards I started seriously blushing and shaking im such a fucking wimp
Me at the end of a romantic snowman-building date with this girl I'd been talking to over winter break: invite her into my room to hang out for a bit longer, she has to go to work right after so she can't sit or take off her jacket or anything, so we're both just standing awkwardly, making light conversation that we both know can't continue for over like five minutes, she has to leave and I'm just like, caught in the limbo of "to hug or not to hug", end up hugging but it's after an awkward pause, she's leaving through the hallway and I just walk out of sight and start silently cussing myself out. And that's set the tone for the rest of our interaction to date.
So, yeah, I know how you feel.