So you have two children, your wife has two children and you have a joint child together?
I’m assuming that contact weekends aside you all live together together as a unit?
And your brother has invited your two sole biological children and the joint one you have with your wife, but left out her biological children?
If so, that’s a really, really shitty thing to do.
I doubt very much he’s done it maliciously though and he probably has no idea how much upset it would cause your wife.
Does he see your wife’s children often? What is their relationship like?
If he never sees them then I guess that may explain why he hasn’t invited them? Not that it makes it ok of course.
I can completely understand why you feel confused about what to do. I’m very close to my sister and if she were to ever get married I can’t imagine not being there.
You are in a very difficult situation and I don’t envy you.
I think you should just talk to your brother. None of us on here know him, his character and his intentions etc but you do.
I’m hoping that he genuinely doesn’t see why this would upset your wife and if you’re as close as you think you are then I’m sure he’d mortified to learn how his invites have been perceived.
Just talk to him before making any decisions and hopefully the matter can be resolved.