To start this story, I am a pretty fresh immigrant to the US, less than two years now and married (F24 with M32).
My husband is a US citizen and grew up here. He has a pretty steady group of friends that I pretty much all know, and I am offered to hang out with, but only do so sporadically because I feel like they’re my husbands friends, he grew up with them, they’re older and ultimately, I very much support him going to the bar with them or play games or whatever. If it’s like a party or an event, I am happy to go and they are all great people.
I started a new job where are I FINALLY after almost two years of not having proper friends and missing everyone back in Europe, made good connections and I hang out with group of people (about 3 to 8 people) pretty regularly after work (we all work at Disneyland, so it’s easy to just pop in for a few hours after work without going home). 
The thing is, as much as I love my husband I also enjoy being a stupid 20 year old and hang out with people my age or a little younger, which is all of them in this group. It makes me so happy that I finally have connections of my own and ‘my’ group, because as a new person in the US I had to rely on my husband for that and had to blend in in his group, otherwise I wouldn’t have anybody and I didn’t have the luxury to have someone I grew up with or like a high school friends I would know for years, and this really bothered me. My husband always encouraged me to make friends, too. 
Here is the thing.  My husband now keeps asking why am I not introducing him to my friends (which he met at least 3 of them when he was with me after work, not in a group but I introduced them, but we never hang out) and wants to hang out with us, but its not what I want. He feels like I dont include him.
I feel like in general I am very independent person and I was never clingy or have the need to spend all my free time with any SO in the past or include them in every little thing I do - I like to think that people dont merge all of a sudden to one entity and have to intertwine everything theyre doing and have like shared friend group.
Also, as much as our age difference isnt an issue in day to day life, I feel like I had to grow up a lot and didnt enjoy my early twenties at all, which  I get to enjoy now with my new friends - my husband being older would totally not fit into this group because of it. I dont want to think about if he is entertained and having a good time with bunch of stupid 20 year olds . 

To add more info, i mostly hang out with them right after work, like once or twice a week, rarely stay out late, they are all good people, no drinking, all very safe and mostly at Disneyland. I would not prioritize my friends over my husband but I sure value my own happiness as well. The time spent with my friends doesnt shorten the time spent with my husband. Also I said majority of these reasons to him but he arguments with that I got to hang out with his friends so its only fair, but i dont value those things the way he does.
Am I the asshole here for wanting my own friends?