@thecatsthecats
user - I bet you've had a lovely life without such petty nuisances sticking their oar in at every point!
People who would treat you like that over an invite never seem to realise that they are displaying exactly the sort of behaviour that puts friends over family.
You have no IDEA! 
Looking back, I realise that most of my extended family were (and still are,) all toxic, grabby, moany, entitled bitches who brought nothing to my life at all, and were sometimes quite catty to me, or pretty much ignored me. I mean, not all of them, but most of them.
And they were absolutely morbidly offended at not being invited to my wedding in the early 1990's. They probably would have barely noticed me anyway, as they would have been too busy lording it over everyone else, looking down on DH's family, shouting over everyone, and getting pissed.
They didn't even care about me and probably weren't bothered about seeing me get married, they were just utterly FURIOUS at not being invited, because in their eyes, they SHOULD have been, because it's FAAAAAMIlY INNIT?
Wankers.
And as I said earlier, they have all turned on each other this past few years anyway. Bunch of arseholes. Just imagine Eastenders crossed with Shameless.... Yeah, Got that image? You can see what most of my extended family is like now.
@ArkAngel
Because my family isn't that big, but when my brother got married he did it abroad with our younger brother and some friends and we saw the photos and it looked lovely and the only thing I cared about in the world was that he was 100% happy.
Good for you. 
This is pretty much how I feel. The only time I would feel upset at not being invited to a wedding is if it was one of my kids. I think most parents would feel a bit hurt at that though.
I agree also with @Bluntness100
Someone actually said up thread it was "unthinkable"not to invite your aunt. Were as I think it's unthinkable for me personally to invite an aunt who can't stand the bride, is rude enough to kick off because her invite is not good enough and who I seldom see and have little to no relationship with. I can see why some would, to keep the peace, but I'd be fucked if I invited folks who couldn't stand my fiancé and thought they weren't good enough to my nuptials. Fair play to anyone who does.
Well said.
Re; someone saying 'people used to invite all extended family to weddings, some 30 years ago...' I do agree with this. (Although I do get that it would not have been the same for everyone.)
But yeah, 25-30+ years ago, it was like this in my world/my life/my social circle... Everyone you were related to expected an invite. And you were laid into by extended family - and your parents - if you didn't invite EVERY RELATIVE, even if you had little to do with them or you didn't even like each other much!!! 
Like a few posters have said, why do people have to be invited, just because you are related?
And it was not necessarily a good thing, as I believe that many brides were told to/expected to invite every fucking aunt, uncle, and cousin, and in-law, even if they didn't like them or had very little to do with them.
Like with me, my extended family lambasted me and ostracised me for not inviting them to my wedding, because 'who the hell doesn't invite family? How horrible, how hurtful, how nasty!'
As I said though, me and DH had to pay for our wedding ourselves, in full, (as both sets of parents were poor,) and no-one helped us. Whereas my cousins had their weddings paid for by their folks! No matter how many times I explained this though, I was still treated like a pariah.
@mumwhite you are entitled to feel slighted and hurt, but not entitled to kick off about it and make your nephew and his bride-to-be feel bad. They probably have enough stress in their lives right now, with organising their wedding and trying to please everyone, without you kicking off.