NM, my advice just be yourself. We're not in highschool anymore and I hate the dating games. As long as we're not pushy and can read the signals in order to reciprocate who cares what the dating rule book says?
Also I don't think he was being defensive about the kids...I think he was trying to impress you by saying he knows summers are supposed to be fun and a bit of 'appropriate' spoiling of the kids is OK with him.
Finally, just like with other things in life you're allowed to make a mistake or two. If not you don't want someone like that anyway.
If it feels OK to YOU then call him and ask him about tomorrow night or give him another option to choose from because he could have plans for tomorrow night.
Me: 35|WAW: 38|D: 6yo | http://tinyurl.com/2dxx7m6 Feb 2006, left, came back in two weeks Aug 2006, left again Apr 2007, filed for divorce Dec 2007, reunited Mar 2010, moved out, filed again