Wait until mediation on the logistics of the D unless you feel your H is willing to discuss things with you openly. Speculating why he's changing is pointless, as you know. Home school v work v freelance are all things you knew you'd have to consider anyway. I think you're more surprised that H brought it up and is pushing this forward. Nothing new or surprising here, I don't think.
On the guy thing. Given the content of your conversation, I'm going to go out on a limb and say that he's definately interested in you. If he was interested in you while you were married . . .
Get your separation agreement in place first. Given that your H is wanting to see other people, there most likely won't be a non-dating clause. Then, if you want to go for a beer/coffee with the guy, go ahead.
BD
My latest
Me: 36 W: 35 2 D: 9 and 5 T: 16 years M: 12 10/4/06: Bomb 10/5/06: Ended A 4/22/07: ILYBNILWY