Is it ever okay to think about an ex?

Question

When you're in a new relationship is it normal or okay to occasionally think about someone you dated for a long time previously?

Answer

Depends on which situations are prompting you to think about them, I suppose. But as a whole, I think it's normal. There are obviously going to be some comparisons early on, but it should fade as the new relationship develops.

Answer

HELL NO, they're an ex for a reason!!

Answer

Cas is right. Early on, you'll think about them for comparisons, good or bad. However, majority of the time they are only fleeting. Just as long as you don't begin to act on them, it's perfectly fine. 
I'm always wondering how previous partners are doing and where life has taken them. Some I approach for casual conversation, others I know only trouble will come.