Leo not Talking

So I have a Leo friend who pretty much likes and flirts with me a lot and I have a boyfriend of 2 years. He came to visit me at work and awkwardly, my boyfriend showed up as well. They didn't communicate with each other until I introduce them. The Leo was looking at his phone the whole time before he showed up and decides to pull the whole, "Oh look at the time, I gotta go!" He was heading to Austin and usually he stays longer. I called him after and he said he didn't know what I was talking about with the whole awkward tension. After that, he recently just got an internship and I congratulated him, nothing. Instead he talked about other things. I wished him a happy birthday, nothing, I sent him Legend of Zelda poster, nothing. Is it because he's giving me space? Pushing himself away? He knows I liked him, but I can't do anything because I'm in a committed relationship, but would like to keep it cool by being friends. Should I just leave him alone or on occasion, I can poke at him?

Update: My boyfriend knows he likes me so during the introduction, he told me he jabbed him with, "Oh, thanks for keeping her company." and the Leo didn't say anything because I told my boyfriend on occasion, he visits me, but nothing of a big deal.

You know, I just realized something....

Leo is the eternal optimist. Maybe, its for good reason.

Cause, when one door is firmly shut, we won't even try the knob. We find a window to fly through to the next door.

Being a friend could be tasking for you if you really like him like that. You may incur heartbreak. Loss of good judgment and other side effects.

You decide

you have a boyfriend so he left you alone like he should