Sorry to hear that GettingBy. Be sure to stick to your plans with the kids of having a FUN weekend. Do NOT let him change your plans.
I agree with Stella. If you find it will be impossible to enjoy your weekend with him around, go to a hotel. I have done that with my kids and they absolutely love it. We like to go to the ones with a small waterpark. I find I can't keep my eyes on all 4 kids by myself in those huge waterparks.
Hope you have a GREAT weekend!