<human>: Me and 19M have known each other for about a year and have slept together repeatedly over the course of the past two months. Non-committed. However, if he were to ask me on a date I wouldn't say no. He's always saying how he doesn't want to make us a thing, so whatever. I got the dick. Definitely nothing to worry about.  
In the past he's always been happy around me. Joking with me. Texting me stupid cat pictures. Really fun. It's why we're friends and have always been friends. I do it back.  
He found out I'm dating other guys for the first time since we kinda didn't have a thing but still fucked each other. At first he was making it a point that he wasn't jealous, even though I never asked. Then he got offended that I never brought it up, because "friends talk about these things". Okay, I'll tell you all about it after it happens.  
Today I told him I had a date tonight. We're coworkers. All day at work he was really short with me and didn't goof off like he always does. Not mean, but definitely not friendly. He canceled plans we've had for a week too with no explanation. I was really looking forward to them. Before the date I saw a penguin gif so I sent it to him. No response. He won't respond. Now I'm home (remember, he got mad at me not sharing before) and he hasn't asked about it. Hell, his best friend has asked me about it and is super happy for me.  
The dude wants no commitment. The dude is offensively jealous (but lol no I'm not) and asks for details. Then ignores me, blows me off, and doesn't even seem to care.  
What is his fucking problem? What do I do? He's my friend, and I want to keep him as a friend, but not if that means I have to remain his backup bitch. Do I confront him? Do I play it off until he caves? What is he even thinking?

Condense the text into a few key points
<bot>: Friend", with whom I've had a sexual past, is blowing me off because I'm dating and generally being happy without him.