I think it just depends on how DONE you are, and how solid you are.
I dated just a few months after my ex left - but ours had been a long long story of infidelity, reconciliation, and 6 months of fighting him leaving. By that time I was really truly done, and the guy I dated ended up being a wonderful experience. HOWEVER - I was also strong enough to deal with the reality of the new guy's issues (he had many) and not to be too broken up when he eventually dumped me for his old college girlfriend (he did it nicely).
I didn't really date for a while after that, but am dating again now. I find that I'm in a really good place now, don't get too attached too early, not devastated if it doesn't work out (hey, there'll be another bus along in a minute!). The key was, I gave up trying to control or be too attached to the outcome. Some of my relationships have taken forms I wouldn't have expected, but I've learned that by letting go of my expectations, sometimes I can appreciate things for just what they are. (The old boyfriend, for instance, has remained a close and cherished friend.)
I've even learned to curb my unfortunate tendency to pursue. When one recent date backed off (for reasons of his own issues which frankly are probably quite valid), I didn't try too much to talk him out of it, although I really really wanted his yummy self. I've learned I NEED a guy who is enthusiastic about being with me, and one who is hesitant or conflicted, however attractive to me, is someone I need to let go of.
