Heimskr.
It was for a serious roleplay about an Altmer who had been converted to the worship of Talos, okay?
I used the console to get him to notice the amulet of Mara fine. He gave this line about how it was surprising I wasn't married, then this proposal about how he'd be happy to stand by my side until the Divines took us, so I trotted off to Riften to arrange the wedding. But he got cold feet and never showed up. I walked into the temple at the right time. There were guests, there was Maramal, but no Heimskr and no cutscene.
I tried waiting, I tried reloading, I tried using the console to spawn him in the temple (that last one was funny as he kept up with his Talos sermon) but I couldn't make the cutscene start. It's definitely something about Heimskr that makes him impossible to marry. I did some experiments with Lydia, then Anoriath with the console, and both those wedding cutscenes began without a hitch.
So I guess my Talos worshiping Altmer is destined for the single life ;_;