How long should I wait?

I'm going to get straight to the point here..

I met this guy about a year ago when I was in a really bad place in my life. We got to know each other over the next 6-8months and I think I like him. We just, click, effortlessly. So after a while, I went away for a few days to build up the courage to tell him and just before I could, it's announced he's got a girlfriend.. bummer.. I leave the man alone.

6 months just fly by ey.

I bumped into him in the pub last week, we sat and had a drink and he told me the girlfriend cheated and now he's single.. so, how long do I wait?