Am I overreacting to my regular's behaviour

I (26) am a regular with a guy (25) for the past 7-8 months. We don't have a huge amount in common - I'm more femme and hes more masculine - but it works.

Last week he invited me on a weekend with him, his mates and their partners. I asked if this is him asking me out. He said he assumed we already were together.

We travelled to a really nice house in the country side. Some of his friends were already there with their girlfriends. I assumed some of them at least would be gay but no. They seemed surprised to see me. They said they didn't know he was "both way". The girls were lovely.

I went over to my regular asking if the girls knew he was bi. He said I'm not sure. I said do your friends know you are bi. He turns to his friends and said did you know I'm bi, lads. One said yeah. The others said no. He turns to me and said no they didn't.

I hung out with the girls more than the guys but that's common for me anyway. The girls spoke very highly of him.

I found it weird how he never told them and then said it so casually. I thought he'd be shy to embrace and stuff around them but he wasn't - kissing cuddling etc. He was like why would they care if I kiss you. I'm not kissing them and he whispered something naughty.

When we were driving home, I asked do your parents know you are bi. He said I'm not sure. I asked him did you tell them you were bi. He said no. I said so how would they know. He said we can pop in to them on our way back if you want? I was like are you not worried telling them you are bi? He said why would I worry and they love visitors. I said so you would take me to your parents without a heads up that you are bi. He said you are acting so strange about this why would they care.

It annoys me, slightly, for some reason. I can't put my finger on it. But how is he that non-chalant about it. Communication. Am I overreacting?