Guy's Behavior

Why does he leave me to fend for myself at the social gatherings he takes me to?

I met a new friend on Christmas through my best friend– she set us up. We went on our first date a few last week and then I went with him to his extended family's house yesterday for new years then an after- party at his friend's house w LOTS of his friends. (I'm pretty introverted but I got out of the comfort zone to meet a lot of his friends w/o his help so I wouldn't look like a complete loser)

Here's the weird part: even though I barely know the guy, he is SO easy to talk to one- on- one. He asks me good questions. I feel like we mesh really well, but I don't understand— the moment we walk in his grandparents' house and his friend's house, he kinda just left my side. He'd occasionally check in throughout the night, but otherwise I was on my own which was kinda scary since I didn't know anyone. Now I know I just met him and it's not like we're dating or anything so I'm not entirely someone he needs to look out for, but I don't know. Is this a red flag? Is this normal for a second date?
Why does he leave me to fend for myself at the social gatherings he takes me to?
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