Most Helpful Guy
I haven't been in this position personally, but two of my best friends have:
She was dating another guy (who she is on friendly terms with now), and that's when he met her and she liked him too but was dating said other guy.
After a few months she broke up with her boyfriend and started dating my friend; long story short, they've been together for about 7 years and married for about 2.
I would say if you and your current guy aren't that serious, then why not?
Most Helpful Girl
Then stop dating the guy you've been dating and ask out the guy you like.