Doesn't sound to me like you did anything wrong. Did you lead him to believe that you were more interested than you are? No? Then don't worry. There's nothing wrong with going out with someone a few times before deciding that they're not the one for you.

No, you're good. You're not supposed to decide the instant you meet someone if you want to marry them. That's why you date .. spend a little time together, see how it goes. I probably sent a lot of nice guys on their way without giving them a fair chance, so you did right by going out a few times and then letting him know how you feel.

Yeah it can be a little uncomfortable to have to say, in essence, thanks but no thanks, but that's the kind thing to do. It would be unkind to be noncommittal when you already know you don't feel romantic about him.

But should I have done it in person at our drink tomorrow or was it better to know now?

Better to know now, I think. If you've decided, then might as well let everyone move on.

After a few dates, I'd rather be dumped by email then to get all dressed up for a date only to be dumped at the bar.

Well, to be honest, you weren't really interested from the get go. That's how you sounded in your comments here at least.
So, yes, I'm under the impression that you led him on.
Better for him to know sooner than later.

But that's one of the risks of dating. It has an essentially selfish dynamic.
'Love is a battle field' as dramatic teenagers once used to sing.

Well, you asked.

There's not a good way to break up with someone, but there are less-bad ways. It'll never be easy, and there will often be issues with someone being felt led on. You just do your best. Yeah, I'd want to know before the next date. A phone call would be better, but if your "relationship" has been mostly email based, that's OK too.

He appreciated me being upfront and letting him know but we are still meeting for drinks so I think things are ok. I think we will be able to be friends, so I'm relieved. I guess I didn't have feelings for him right away but I wanted to give it a shot to see if something would develop because he was a nice guy. Is that really leading someone on? He said he was disappointed but not so much that he doesn't want to meet for drinks, so I don't think I wasted his time.

I don't think it's leading him on to have gone on a second date to see if anything developed. I think you let him know at the right time.

I guess I didn't have feelings for him right away but I wanted to give it a shot to see if something would develop because he was a nice guy. Is that really leading someone on?

This sounds absolutely sane and reasonable to me. It's not always easy to know if you're romantically compatible with someone after one date, and if you know you're socially compatible with them, it's doubly hard to tell: do I like them, or do I like them? Going on another date is a perfectly sensible way to find out. Once you did determine that he was a potential friend, not a potential partner, you told him.

It's hard to imagine how else you'd handle this, really.

Yeah, you're always going to come up against that problem:

Person 1: Why did you get my hopes up and kiss me (go out with me, sleep with me, etc.) if you don't see anything further between us?

Person 2: How am I supposed to know if you're a good kisser (etc.) or not if I don't try first?

Right on, amro and others.

I think you handled it fine.