The date was okay. He's a very nice, smart guy and would be fine to be friends with, but there's no chemistry on my end. I don't think he feels the same way, so I've got to figure out how to nicely tell him I'm not interested in anything more.
Just be honest about where you are emotionally and that your just not feeling it. I'd rather have someone tell me honestly, (obviously don't be cruel) than for some bs line. I'm sure you already have this figured out though.
You can not change your past, but you can ruin a perfectly good present by worrying about the future.