My group decided that the real reason behind the Scorpion marrying once wasn't out of any amount of true devotion to their spouse or anything -- it was for the very practical reason that if Scorpion only married once and their spouse died they couldn't be shipped back to their family. Now, the Scorpion clan has a "former" Scorpion spy in another clan with no particular ties or vows to anyone else but their clan.
There already IS an emotional unmasking ceremony WITHIN their clan, but it's not quite in the way you're suggesting: Scorpion never wears masks to any Scorpion's wedding, birth ceremony, or funerals and they're all big, buoyant celebrations: birth ceremonies and weddings can go on for days. Famously, for weddings and funerals -- not so much births -- anyone who happens to be nearby and a samurai is often welcome.
Weddings aren't really sad ceremony though; Scorpion plan those things out to serve their clan from practically the first day everyone's sure you're safe from childhood illness. You're fulfilling your clan duty by marrying well and to the benefit of the Scorpion clan, after all. Marriage is about a contract between clans that helps achieve a greater end... and if skillfully done? Puts someone you can trust in a position to complete further goals.
"Once a Scorpion, always a Scorpion"