If I had to guess, it sounds like you are dealing with much bigger issues and just need to vent. Which I see you have done.
Weddings are a stressful time for everyone, and for broken families even more so.
I know you are sick of putting yourself last...but really examine this. How do you think your DAUGHTER feels? Her father is the same man that you are referring to! She has to deal with it too! And she has to worry about all the other stresses of planning a wedding in this day and age on top of that.
You daughter simply wants to have a fun family affair. 3 day "wedding weekends" are not unheard of. Most people enjoy them. She is not trying to tourture you! Remember that she has to consider herself, her fiance, and the wishes of other guests too.
If you do not want to stay for all 3 days, don't. Take your daughter (and her fiance if you wish) out for a private dinner before the wedding. Then stay for the ceremony/immediate reception and fly home. I'm sure not all guests/relatives will be staying for the entire 3 days.
Or, tough it out and make this one sacrifice for your daughter. Don't punish her for things outside her control. I hate to sound mean, but it was YOU who married her father and had children with him!
Sorry for the tough love, but divorced couples need to stop acting like children. It's behavior like this that leads to divorce in the first place. Life is about "rules" only if you see it that way. You could say your daughter has set "rules" by having a 3 day wedding weekend, but I see nothing to suggest that. She is living her life and doing what makes her happy. Don't let your immature husband or his new wife stop you from living yours. Isn't that what you want to avoid?
It sounds like she is desparetely trying to ensure that her feuding parents follow some sort of decorum by setting likely harmless "ground rules". Or perhaps she is so stressed that you 2 may fight that she doesn't want you to come at all. Talk to her. She is probably hurting and stressed more than you know.
In the end, if you really just don't want to attend a 3 day weekend event for your daughter's wedding, then do not. Be upfront on honest about your reasons, provided you really don't like golfing, BBQ's, socials, etc. and would rather just stay for the ceremony.