Why would a guy act nonchalant AND jealous?

Anonymous
I have a huge crush on a guy, that I know has a crush on me too. We work together, and he often goes from extremely flirty to almost completely ignoring me. It drives me crazy! I can't tell if he's trying to keep up a poker face, or if his feelings are actually fleeting. I feel like my feelings are at the mercy of his mood swings, which is annoying, so I end up acting just as distant as he acts towards me.

Recently, there is another guy at my job who I hang out, joke, and laugh a lot with during the day. He is attractive, but it's totally platonic between us. Still, I've noticed my crush watching us. Instead of joining our conversation, he listens from the sidelines, and when he's brought into it he acts kinda awkward. Also, with out even doing it on purpose, this new guy manages to interrupt conversations that my crush and I are having. He's like the ultimate c*ckblocker, without even knowing it.

This whole thing amuses me, because I don't get how you can act like you don't care and then act jealous. He used to hover around me when he saw me with guy friends that he didn't know, but this is his coworker too. I'm not flirting with the dude, and he's not hitting on me, so what gives? It's also not like my crush is actually trying to date me, based on his non-action, so how can he be jealous?
Why would a guy act nonchalant AND jealous?
4 Opinion