And at least you're giving him the comfort of knowing his personality rocks?
Or let him know you felt like he was too aggressive, so next time he'll know to be a little more laid back.
Whatever the problem is, identify it and let him know it was big enough to be a deal breaker for you.
The "telling him you're done" part is easy and self-explanatory.
You say just any variation of "I can't do this anymore" via text, phone call, or in-person conversation (yikes).
He was rediscovering himself as well as discovering the modern novelty of online dating.
Baggage rarely matters in the early days of dating.
As far as being nice goes, this is probably the meanest. So if you're doing this, make sure you let him know that you understand if he doesn't want to be friends.
Sure, friendship sounds nice in theory because you like this person and you want to be friends with him! Do you really want someone telling you they like your personality, but they're essentially not attracted enough to you to want anything more?! As much as it sucks, the fact of the matter is it's the truth.
Maybe it's not just work or your ex or your family. If you have a ton on your plate right now, it's perfectly valid for you to not have room for a relationship on top of everything else.