Thanks for all the advice on my post yesterday ya’ll (gotta throw in some of my southern charm here 
)
It’s just difficult knowing how to act / what to do because we were friends for so long and our friends are sort of friends with him - AND he’s been talking about “how fun” our wedding is going to be for over a year or so, assuming that he was invited already!!
He moved to another part of the state around 2 years ago, and we rarely hang out or even talk online anymore unless he needs something and/or is bored.
How do you break the news to someone that they’re not invited, when they already thought they were coming?? 
If you feel bad about hurting him, totally blame it on the size of the guest list. If forced to elaborate, say your parents and Mr. Plum’s parents are each inviting 200 people (or whatever the size of your wedding is–just make sure you pick a number that’s more than 2/3 of your actual wedding 
and that left very little room for your and Mr. Plum’s friends, so you had to be very brutal about picking your people. Complain a lot about what a circus it is, and how you’re ready to kill your mom and Mr. Plum might never speak to his aunt again, etc.
But be prepared: since he himself is not married, he probably will not understand Guest List Torture. He will be hurt/offended, and complain to your mutual friends, and he may eventually find out that the real reason is that he has been a jerk and you just didn’t want him there. How he takes this news is up to him, but hopefully by the time he finds out, he will already be resigned to not coming!
I think Miss Manners would say, since he’s putting you on the spot for an answer (meaning you can’t just let the non-delivery of an invitation speak for itself; ideally he should have already figured it out and not asked you) to tell him something like thistleorchid suggested.
If it’s common knowledge that it’s a big wedding, instead of saying it’s “intimate” you can still say, “I’m sorry, but our venue/budget requires a limited guest list.”
Also, if in person, use face/body language to communicate and underscore your words — a tipped head, winced oh-shucks smile, crossed arms, etc. sends a message, too. (I still can’t tell whether you are trying to continue or terminate this friendship? If the latter, this is some opportunity to do it.)
A normal person (is he one?) would read between the lines that he didn’t make the cut.
By no means is there any reason for you to explain anything more, and being too honest runs the risk of backfiring.
Personally, I think you don’t need to say anything at all. Simply not sending him an invitation clearly conveys that he is not invited.
If the date gets closer and he asks again, just let him know that he’s not invited.
If he asks why, I don’t feel like you need to give a reason. If he keeps pestering you, just stop speaking to him. It doesn’t really sound like he’s a friend you’re looking to keep around.
Good luck!
Don’t think there’s an easy way to do it. I’d tell him the truth as tactfully as possible. If you try going the “we’re under strict limits,” or any other excuse route, he can always come back w/ an argument (”well I know Bob can’t make it cuz he has that thing. Can’t I just take his place?”) If you tell him straight out that he’s too distant a friend nowadays (physically as well as in relationship terms) and that it’d be weird to have him there based on past parties, he can’t say much.
No matter how well he takes the news, you’ve basically burnt the bridge on that relationship. But in the case of Joe, it sounds like you’d be better off that way 
be as honest as possible — dont try to sugar coat it or place the blame elsewhere. you just need to tell him point blank, he’s not invited and there’s no room for him on the guest list. if you try to play it like it’s out of your hands, but you actually wanted him there — this guy will find a way to force himself into your wedding. i find being upfront with guys always works best.
Mrs. Plum, Dallas
Age and Occupation in 06: 22, Accountant by day/Floral and Event Designer by night and weekends
Fiance's Age and Occupation: 24, Security Admin
Engagement Date: December 31, 2004
Wedding Date: June 29, 2007
Venue: Marie Gabrielle Restaurant and Gardens
About Me: I have been engaged for about two years now - yes, a long engagement, because my fiance and I wanted to wait until I graduated college, which I did this past summer! He proposed after dating just two months - crazy, I know, but 2 years later, here we are, still crazy in love :-). We are having not one, but TWO weddings and TWO receptions in one weekend - American-style and Vietnamese-style - in Dallas, Texas, where I was born and raised!
i had a very similar situation. I simply said “I’m so sorry there’s been confusion. We really wanted to keep the wedding intimite and couldn’t invite everyone we knew.” Although that particular person wasn’t malicious, just assumed she was invited but had been pretty distant recenty.
In your case, given the person in question’s seemingly agressive behavior, I may take a harder line with something like. “Look, I’m sorry that you assumed that you were invited to the wedding but we really would perfer to keep our guest list to those who we see frequently and whose company we really enjoy” (maybe leaving the last part out, your choice) Good luck!