This is one of those things where you ask 10 different people and get 13 different answers. It would also depend on what you mean by ‘move on’.
Personally, I don’t think you are ever “done” with your twin. I always thought of myself as having the ability to cut bait, and I’ve walked away from a three-year relationship with a karmic without batting an eye.
But I can’t imagine ever actually moving on from my twin. Even if it doesn’t work in this lifetime, I think you’re destined to come around again.
But people have got more into it here (I would read that thread):
Some people go through separations lasting years and don’t move on. Some of the success stories have couples who come in and out of each other’s lives over long time periods and find each other in the end.