There's a guy at karaoke and I swear he's checking me out (tl;dr at the bottom because I ramble)

So, a few things to clarify: I am in a relationship, and one of the foundations of it is that we can fuck around as long as we're honest, safe, and come back home to each other. Half the time this is happening, my boyfriend is sitting next to me getting a kick out of my low-grade freak out.That said, there's this guy at the karaoke night I frequent. He's an older guy (I'm 28), he looks like maybe 40s or early 50s, and he's gorgeous. I already have a weak spot for older men, but he hits that "shy English professor with glasses" thing dead-on and it's distracting as all hell.He also has a swoon-worthy voice, which reached now heights this past week when he absolutely nailed Bowie's "Let's Dance", dancing around and everything while he did. My gay little heart about exploded, and I was basically screaming in my friend's ear the entire time.This guy is also very sweet, and always chats a bit with all the other regulars, but I swear he's watching very intently any time it's my turn. My friend is the one who started the "I think he's checking you out" thing, and while I tend to be incredibly clueless, she's almost always been dead-on accurate about that. After almost every song I've done, he'll come over and lean quite close to tell me that my voice is phenomenal, that I now own that song, etc. According to the same friend, he also tends to just keep looking at me throughout the night, and again while I'm a clueless little fucker, even I was catching it this past time. We kept almost making awkward eye contact and then breaking it off.We were at the same bar a few nights ago, not for karaoke, and he was there again and stopped over to talk with me a bit, again super close to my ear, about looking forward to seeing me next time and agh, I'm losing my damn mind.I'm pretty obviously gay, at least with the usual karaoke crew; I sing a lot of Gaga and Queen, I'm almost always wearing at least one or two rainbow bracelet, and I've made plenty of "me too!" comments when the MC says something like Bowie was her first crush, or staring at posters of Jim Morrison as a kid, etc. The whole regular crowd there is wonderful, and I feel crazy comfortable around them. This guy though, I've got no idea. I definitely get a bit of a 'gay vibe' from him but I couldn't say why, and I definitely can't confirm it and there's really no polite why to say "Hey Bob, are you cruising the shit out of me or do I just have a raging schoolboy crush on you and your handsome ass?"Idk guys, what say you?tl;dr there's a guy at karaoke that I have a ridiculous crush on and it may or may not be mutual but I have no goddamn idea GIVE ME ADVICE