Distraction with something exciting may help. A new project. Sign up for a weekend sailing. Go on a long hike, or overnight trip with some local club (not alone). Sign up for a class to learn something new and potentially interesting.

Don't seek out new guy yet, because chances are he will be reminding you of the ex and the good stuff that you miss, or of the bad stuff you walked away from, and it is more likely your judgment will not be optimal.