I know from talking to them they will be a bit uncomfortable.
They will cue off your lead. Don't you think your wife feels a little uncomfortable too? Incredible opportunity to shine. Maybe it's time to have a small R talk about how you are going to handle this weekend. Give her some security and assurance. Use the party to fill her love buckets. When you show her LLs in front of family it is powerful.
Cheers
As usual, GREAT advice Coach.
OK, so I am trying to go through that R discussion in my head. Thinking something like:
GIMA: I'm really excited about D's birthday party this weekend. W: Me too (maybe a bit nervously). GIMA: You know, I will handle step-mom and SIL, but I don't plan on discussing anything about us with them. I would imagine they might feel a little awkward, and I would not be surprised if you felt the same way. Is there anything I can do to make you feel better or more at ease about that? I can run interference for you with them. Honestly, I think they just want to enjoy D's party and enjoy being around us. In the end, I want to do what I can to make this as easy on you as possible.
OK, might need some fine tuning. And I'm open to suggestions.