So - if you contact him and he doesn't respond enthusiastically, are you going to be disappointed? EXPECTATIONS are the problem here - if you're secretly hoping you'll tell him you're dating and he'll wake up and say "No, don't, I never stopped loving you".....then you definitely shouldn't contact him.
If you just want to make sure that door is completely closed (2 years after your divorce) before getting serious with someone else - then fine, contact him. Just be sure you can handle it if he tells you how happy he is with OW, or that they're engaged, or she's pregnant, or some such.
