Let's be real here - the likelihood of your friends being the type of people your partner would hang out with is pretty low. That's not to say they're not great people, but the chances of them becoming besties is pretty slim. However, despite all of this, if your man loves you, he'll go to great lengths to fit in with your friends.
He will take note of the group dynamics, figure out how to make all of them laugh, and pay attention to the things they say. He will hang out all day with them at a group event without complaint, because he knows these are your people. He'll even put aside his differences to keep the peace with some of your more challenging friends. You know that when he's doing things like that, he really is in love with you.