Is it weird if I ask someone I barely know to hang out via Facebook message?

I am currently in my third week of freshman year at college. At a weekly dinner event at a coffee house near my, I met this super cute exchange student from Amsterdam who's 20. I hung w/ him and some of his friends for the rest of the night. He seemed like he was flirting with me a ton but I did some fb stalking and he's been dating a girl for 3 years. This week, I go to the event again and spend all night chilling with him and some of his friends and AGAIN he's acting like he's in to me. At the end of the night, one of his friends added me on facebook so I added him. So I wanted to go out tonight but don't have anything to do/anyone to go with so I'm considering fb messaging him (he doesn't have an American number so he only communicates with people through fb) and asking him what he was up to. I know her parties, he really seemed like he wants to chill with me but at the same time I wouldn't have to worry about getting hit on since he has a girlfriend. Would it be weird since I added him on Facebook and we've only hung out twice?