Answer

It is commonly thought that an Ashkenazi can, but a Sephardi cannot, obtain an annulment, because the author of the Shulchan Arukh wrote to wait six hours (or at least five and a bit). But in my opinion, annulment is possible for Sephardim as well, provided there is a reason for it (grounds for release and regret). For example, when you accepted this custom you did not know that there were other options as well, and that this is a custom, and that it is difficult for you, etc.