No wedding invite for my

In the scenario you’ve described you’re an acquaintance of the bride and groom, and the groom doesn’t see his friend often, so the main / only reason to invite you would be etiquette. For many people, eg with big families, friendship groups etc, that wouldn’t be enough.

I personally think it’s rude and I would expect my partner to put me first and refuse an invitation to the actual wedding but accept the invite to the evening do which you can both attend together.

Unless the wedding is very nearby the logistics of both getting there separately may also be difficult.
I wonder if some of this is a generational thing, but in my day established
( normally married in those days) couples were treated as one unit.
I can see some circumstances where the happy couple has never met the SO due to being work colleagues, etc, where it might be reasonable to only invite one half of a couple. Otherwise expecting one member of a couple to attend a wedding which joins another couple doesn’t sit right with me.
Unless one of us didn’t know the bride and groom I can’t see my husband attending a wedding without me, or me without him.

My husband has some friends they I haven’t really got to know and some who are like family now. If he got invited to the wedding of friends that I hadn’t really got to know I don’t think I would be offended and might actually feel relieved.

Weddings are very personal things and that question of “how do you know the bride or groom”, can be a bit awkward when one says “oh I don’t really know them that well, I’m here with my husband who is a friend of the groom” or words to that effect.

I attended a wedding recently where family members who were not that close were not invited, but I did hear that they were upset because they weren’t. Where do you draw the line?

But saying that do try to not be too upset, it’s their day and they can invite or not invite anyone they want!

Well it would lead quite naturally to the question….

did you invite them to yours?

Your OP says ‘I have met his friend and partner a few times and have been out together as a couple twice’. If in ten years that’s the extent of it then you’re just acquaintances.

In a decade, you have been out twice with his best friend and his partner?

No I didn’t mean for weddings

I mean dinners together? A drink at the pub together? That kind of thing

Could it be that evening invitations haven’t yet been sent out?

How much time have you spent with the groom over the years, and do you get on well with him?

asking as you’ve said you’ve only seen the couple getting married, as a couple, a couple of times.

If your DP is truly the groom’s close friend it’s a faux pas for the groom not to invite you. but less so if the situation is something like the groom lives miles away from you, you personally see him only rarely and are like acquaintances.

As you think the evening is 50 guests more, possibly most of those are “partners/spouses of friends”

Total agree.

It's become style over substance in many cases.

Are other friends from the group getting plus ones, or not?

quite ironic considering it's meant to be a day of love and joining together and should be shared with partners.

Hmm, you're adding the 'should be shared with partners' on there for your own ends. There's nothing specific about one couple getting married that means it should be shared with other people's partners. And if you're so into this big important meaning of weddings, you'd be married yourself, but you're not and that's fine but then don't get all intense about needing to be at other weddings.

I feel a little disappointed in my partner for accepting the invite for himself only for the ceremony without his SO joining him.

Bit mad to feel disappointed in your DP. He's been invited to his best friend's wedding, of course he's gonna accept the invite and not make it a point of principle to only go if you get an invite. Whether his friends don't like you or think you don't like them or just want him there for whatever reason doesn't alter the fact that he'd go to his best friend's wedding. Don't make this some weird test of your relationship. They're his friends, you haven't even had a wedding so don't set that much store by them, and it'll probably be boring anyway so let him go the same way he'd go to any number of friend's events without you and you do your own thing.

Coming from someone who planned a wedding within the last year, we had to make some really tough cuts and decisions with regards to our guest list due to the fact the venue only had room for a certain amount and we both have multiple siblings who all have multiple children. This meant the number of spaces we had reserved for friends was very small.

You’re in your right to feel a little hurt but don’t take it personally or take it out on your partner.

Why is that relevant? They have three children and been together 10 years

Has he had much interaction with your friends?

It’s expected because it’s quite common for wedding invitations to include both the friend of the bride/groom and their partner.