Is this really about when you can publicly acknowledge you are seeing someone else, and the rest of your community won’t go crazy, and brand an A on your forehead?
I mean, if we care what others think, then there is no rule. For some people, any time is fine. For others, it will never be ok to date again (like your priest, unless you get an annulment).
I think this is a question you have to ask yourself. When will you feel ok about it? What conditions will have to be met for you to feel ok? If you never feel ok about it, you’ll have to accept that, and go on and do it anyway. Guilt is a wondrous thing, isn’t it? (that was sarcasm)
Truthfully, I think this can be a very hard time, even if you have been separated for a long time. You kind of have to reorient the way you think about yourself. No matter how bad it might have been, you were still that man’s husband. It will take a while to get over that, and truly be ready to move on with your whole heart and being.