Big smile, hold out your hand.  "Hi, I'm MissKO3".

I dont think I understand? Why don't you just go up and introduce yourself?

Have you asked him why he doesn't introduce you to them? If so, what is his reasoning?

From the little bit you've told me, the GF sounds like she has poor boundaries if she is the one always initiating hugs with your SO. Could it be possible that your SO doesn't want to hang out or be friendlier with them, so he keeps his distance other than to be polite? Or maybe these folks are suction cups who will attach to you two and he wants to avoid that?

If he doesn't present you with a good reason as to why, then feel free to walk up and introduce yourself. But if these are folks he doesn't hang out with despite hanging out with one of his best friends, I'd assume that he doesn't want more than a surface-level relationship with them. Since he has to work with them, I'd let him make the call on what kind of relationship he wants you two to have with them.

It is odd that you've seen them repeatedly over the years, and he's never introduced you, they've never introduced themselves to you, and you haven't just gone ahead and introduced yourself. But I can see how it would get harder to do after you've already seen them multiple times. 

Personally, to me it doesn't matter how superficial the relationship is, if someone is with you when you encounter a person you know, you introduce the two of them.  The hugging is weird, if he barely knows her, but some people are huggy that way.

It is weird. They are at the bar often, your SO works with them, the GF hugs your SO, but he has never once introduced you?

No matter what your SO's relationship with them or whether he does or does not want to hang out with them, he should introduce you. I can't imagine a guy hugging me every time he sees me and I don't introduce my DH. It is just common courtesy.

Introduce yourself, maybe mention how rude your SO has been, not introducing you sooner. It doesn't mean you all have to become best friends.

It's not you. Your SO is being rude...but so are his co-workers for not saying anything. Have you been in similar situations where your SO doesn't introduce you? Is his family a little lacking in the social graces? I ask because my DH's family do so many things that I find rude and disrespectful (e.g. they rarely if ever respond to emails or texts from anyone, they never let people know the details of any gathering, they are always late (in some cases hours late), that I can only surmise they view as normal because they never get offended. I've talked about this at length with DH and I'm not sure he sees that they are rude. I raised one issue with MIL and she totally gaslit me into believing I was the problem for daring to say anything. So, maybe your SO was just raised by wolves like my DH and doesn't realize that he's being completely rude. Doesn't make it any less disrespectful, but would at least provide some sort of explanation.

My DH knows everyone. He is a musician and distinctive looking. We've gone halfway across the country & he still runs into people he knows. My DS makes it a running joke, "I wonder who will know DH here?" He is usually good about introducing me, but sometimes he doesn't. When this happens, it's because he thinks I've already met them (& to be honest, I may have) or he can't remember who they are. If you've run into them several times, are you sure he doesn't think he's already introduced you? 

I usually just smile & say - "I think we may have met but I'm sorry, I can't remember your name, I'm Simifan." I think your putting too much thought into it. Ask your SO what the deal is & introduce yourself next time. 

The women who have hugged my husband in my presence I don't know, have always spoken to me and introduced themselves. At this point whether you were formally introduced or not she should acknowledge you.

My DH is a little jealous, the result of his lack of commitment after several years of our long-distance relationship. As much as I loved him, I began to tire of the travelling and was increasingly tempted by offers from local gents. Back in the day, I was a fine-looking woman, knew it and used it to my advantage. When I advised DH that I was interested in dating, he flew into a jealous panic and begged me to marry him. 

If DH were in your spot, watching a decade-younger co-worker hug me (for 15 seconds, YIKES!) in a bar, he would have lost his composure. Think about this for a minute, MissK03. How would your DH feel if the roles were reversed? Some unintroduced rando grabs his wife for a 15 second hug and he’s okay with it? When some of his co-workers/acquaintances are present to view the action?  Oh, HAHAHAHAHAHAHA!

As the Scots would say, “Your husband needs a tellin’!”