What do you think about me talking to my ex behind my wife's back?
You get along with your ex?
Yes, I find my ex a better person to collaborate with.
I'd say it's not a problem but you're doing it behind your wife's back. Don't ruin your marriage over something you should have left in the past.
My wife is too insecure, and I can't collaborate with her.
If you feel this way about your wife, then you need to have a long hard look at your relationship. Seeing your ex behind your wife's back won't fix any of your relationship issues and may just make them worse.