idk why this is making me so sad

So I have liked this guy for awhile. He is super nice, believes a lot of the same things I believe in, he’s respectful, he’s kind. Like I REALLY like him. I thought he liked me back because he would always talk to me, low key flirt with me, and we would talk a lot. But earlier today I asked him why he was going to go to a different high school than I was going to and he said it’s because his girlfriend is going there. So, did he just flirt with me because he is a flirtatious guy or because he liked me or because he’s a player??? Or did I mistake the flirting with kindness? Anyway, I am just really sad for some reason.