No, she didn't died in any of his timelines, she just ceased to exist. The 100th remember her because they met as children. Aillete exists in only one timelime, hers. So neither Reed or Terry knows about a future beyond her life, like as a married couple or whatever. Just think like that, everything we are reading now with Aillete is the present and every other timeline is the past.
Maybe it was the tl, but in the novel the bible of truth tells him that she doesn't exist not that she's dead. It was never expressly stated, but I think the TM gods (lord voice in particular) are more powerful than the bible and so they (and by extension Ally) exist outside of the bibles range of accessible knowledge so it can't/doesn't have the ability to know. Basically from his pov the world has been gaslighting the hell out of him for centuries with "the girl who never existed". HazyAgate is completely right, right now we're seeing Tez's previous loops with the nonexistent Ally, and the circumstances leading up to his fall into corruption like we just saw. THIS is part of what I mean when I say this season will be much darker. Unlike with the harpy queen they can't just effectively skip the dark, messed up parts without effectively destroying the whole story.
Am i the only one getting emotional hahahhahajsdhjedodjjf like its revealed reed is his 100th regression and we see him in his 90th asking where ailette is that means she died and he had to go through life again without her AAAAAAAA NOT ME CRYING MY BALLS OUT and imagine when he finally saw her again in his 100th i just know his heart sank or mostlikely maybe a distant missing her cause it was such a long time