Yes, given the situation and with the party being at your house and all, not inviting them definitely sounds like the best idea. It's interesting that you want the group outing with H tho for S's actual b-day to continue on. H has chosen not to be a family, so I'm not sure I would give him that benefit. S is pretty young, so he may not remember that the group dinner is "suppose" to happen from his 1st and 2nd b-days. He is 3 now and obviously more aware, so you are going to be getting some precedences with him too. Do you really want H to be joining you for the rest of your lives? I know it will suck for you in some ways b/c you might (depending on H) have to give up S on his every other b-day, but this is a D and that is some of the sorrows we must face. If that's a tradition you would like to keep, it's definitely up to you, but just something to think about too.
Regarding H's comments to stay around and help, it's hard to say what his exact motivations were. In any case, it's not surprising to say that H still cares. Despite what our H's have put us thru, we still care and would do something to help them out (within reason) too. You have developed feelings for someone over a long period of time and they just don't go away instantly (even though, sometimes we wish they would to protect our own hearts). Just keep doing what you can. If you need the help, take it, but try not to look too much into it either.
Hope your weekend went well. Were you able to get all the party stuff bought? One more week until our S's parties! Yay! =)
Me 27; H 28; S 2 Togeth 9; M 4 Sep 11/14/08 EA OW1 Sep 08 EA OW2 Mar 09 EA OW3 Jun 10