@ByScott
I've not read the whole 23 pages...but I think you should attend your brothers wedding. Asking you not to is ridiculous.
Stepchildren are not the same as your own kids and if he has a tight budget... I can understand him not inviting them.
It's not about your relationship with the stepkids ...it's about your brothers relationship with them.
If he's not so close to them I can see why he's not invited them.
I'm sure you wouldn't insist she boycott a family members wedding if your kids weren't invited would you.
I find it terribly controlling that she's asked you not to be best man.
You and your kids should go. Your wife can stay home with her kids.
*People need to remember that as much as you have equal treatment within your blended family...
you cannot force others to see stepchildren the same as their biological nieces, nephews or grandchildren
The sooner people realise this, the better
I see too much of how stepgrandkids got a cheaper gift etc