What does it mean when a guy is (too) comfortable around you?

Anonymous
I went on 2 dates with this guy, although he already kinda knew each other before. Our first date was nice, we talked and laughed for hours. The 2nd one as well, but it was easy to see he was much more comfortable around me than I was with him... It takes me a while to trust people, so I was surprised how easily he could talk about everything, his friends, family, his not so good qualities... But all in a fun way. We kept laughing and I guess blushing at each other. How uncool is that?

I'm used to guys always just showing their nice side on the first dates, so I'm wondering what's different here?

On the other hand, we always got along much better in person than over texting, as I can't tell there when he's joking or not (seems he likes to playfully tease me sometimes).

Last time I was getting upset and was trying to ask if what he said was just a joke or he really thought like that, but then think he took it the wrong way and we ended breaking up?

How can someone really open up to you in a moment and get super mad in another for no special reason (not to me anyway)?

Think he's thinking I wanted to break up and found an excuse for it, but it's not true. I feel like texting him again but not sure I should at this point...

Any insights on this behavior would be great.
What does it mean when a guy is (too) comfortable around you?
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