I am Latvian and that is no wedding tradition I have ever heard. A second wedding usually isn’t a big deal like a first wedding anyway, but you can still do all the normal traditional things. Having an ex at a wedding is not common at all. Defiantly not part of the ceremony, whether you do it at the registry or church.
I realize this is a troll post, but no reason to make Latvians look crazy. We generally take weddings seriously but they are also a lot of fun (like kidnapping the bride).