<human>: Can you condense the text into three sentences or less?

Me and my boyfriend have been together for approximately one year. I love him very, very much. Our relationship has been going really well, but there's just one thing.. 
I really don't like his friends. I've met them a couple of times and there is just absolutely no connection between me and any of his friends. I just don't get their sense of humor (while I think my boyfriend has a great sense of humor) and their interests don't match mine. I've really tried to connect with them several times, it just doesn't work out. I'm quite an introverted person and I find it quite difficult to meet new people, but I really tried my best to open up and show interest in them. I just feel really out of place whenever I'm with them. I feel like they would rather not have me there. His friends have already expressed several times that they think my boyfriend spends too much time with me and not enough time with them, so I feel like I'm only a burden to them when I'm there.

My boyfriend doesn't seem to notice. This is partly because I always tell him I had an okay time after we've met his friends. I'm never too enthusiastic though, that seems unfair to him because it's not true. He has never asked me what I think of his friends, so I never told him I don't like them.

He has one of their birthday partys coming up and I'm not sure what to do. He has asked me to join him. I'd rather not go. Do I need to join him and go to the party and pretend like nothing is wrong, or do I need to be honest with him and tell him I'd rather not go? He knows I'm not a big party person, just not that it's also because I don't like his friends.
Am I just being selfish for not wanting to go?

Perhaps it's important to note that he has met my friends on several occasions, and he does seem to get along with them. Then again he is a lot more extraverted and social than I am.

Excuse any mistakes. English is not my first language.
<bot>: I really don't like my boyfriend's friends. There is a birthday of one of his friends coming up, should I go or tell him the truth?