Not just that, but the hints dropped in her Character Events like Under the World Tree and especially Crash of Thunder were pretty strongly pointing at that being the case.
This is true, but there have been clues that the basement of the school, specifically the boiler room iirc, holds some information that the powers that be don't want Sensei to know.
What is it with the boiler room? I've noticed a lot of you mention it, but I can't recall when it was said in LiL.
I also thought it's under the school, but only because of the happy event that takes place in a dark classroom. With no light, it's likely to be underground. And it's a classroom, so...
He does glitch in the current paid update when Noriko starts going on about some stuff that happened after the accident.
But Niki tells him quite a lot about his past and outside of the letters and a jumpscare that felt more like a meta-joke than an actual in-game event, he's fine.
So it feels more like there's something very specific about that period that she's trying to keep him from finding out.
Let's see.
As I understand the timeline (please correct me, I'm writing this with the need to sleep and slight alcohol consumption):
Original Sensei has a brother and lives close to the Nakayamas.
His brother also has a wife and daughter.
Sensei wants to become a teacher and grows close to the Nakayamas, particularly Niki, who he has a relationship with.
Sensei seems to also have had an affair with his sister in law, with her "grooming" him, evident by her teasing and well, the happy scene with the teacher (who is likely the sister in law and his inspiration for becoming a teacher).
The car accident happens and Sensei takes Ami and moves away, not informing Niki of his whereabouts.
Sensei lives in an apartment, simlar to Chika's current residence and tutors a multitude of students, despite having a questionable mindset in teaching (likely due to past experiences).
Among these students are Maya and Noriko, who found him.
Maya is similar to Sensei and they grow fond of each other, likely starting a relationship.
Noriko sees Sensei with someone "redacted". When I read this line in the update, I thought it would be Ami's mother, but she would have a slight case of being dead at this point in time, so I wonder who this could be?
Maya reaches high(?) school and may or may not have been impregnated by Sensei.
Sensei, unable to bear responsibility, decides to jump.
From here on it's unknown what happened leading to the resets, but Maya praying despite not really believing in god may indicate that she made a deal with either one or multiple gods to bring him back.
The revival was not 100% successful. Either different aspects of Sensei became the temporary main controller of the body (such as the one that wanted to be a good teacher, evident by what his reputation is before changing his teaching style) or different people were placed into his body (if we consider something like souls as balls in a basket, then a random ball was taken every reset while trying to find the "Sensei ball" (also haha, ball)).
Which brings us to the playable part of Lessons in Love, where we have dead Nozomu, Wire God (assumed to be User2) and unknown third god.
I was going to go somewhere with all this text, but I have no idea what I wanted to say, so enjoy this hopefully correct timeline.
Honestly, I have a feeling, that either I won't make it out alive to see the end, or something will happen with Sel, or something will happen with the world. If only we had a cloning technology to replicate Selebus x10... Oh well, it's about the journey and the friends we made on our path (personally: none

)
Perhaps the real treasure was the pregnancies we made along the way.
Also we may not really be friends, but we're still fellow enjoyers of Lessons in love.
Average pirate who's looking for porn in LiL (and doesn't know the word of the day):
Average LiL story, character and mystery enjoyer: Alex and the (hopefully) majority of us
honestly its getting a bit difficult to separate pre-loop and current sensei anyways, if you take away the interference of other users/angels/gods then characters have noted we are acting 'like we used to', Maya clearly also (probably) thinks the same, and we remember things that 'we' (mc sensei) was not present for when talking with Noriko. lo has mentioned trauma repressed memories, etc. Perhaps theres more to the mc sensei than we're being shown.
lo mentions memories repressed by trauma, Noriko's entire character is 'our' memories, Maya's too (to an extent, and in a different way), Yumi is always around when we have trance-like fugue-states where we lose all of our memories of what happened during them (Noriko too, now that I think about it), also Yumi has asked us if we've lost memories, there might be a clue somewhere here for somebody more invested than I to decipher
oh and unrelated, but, can one of the lore-buffs explain what the deal is with the detentions old-sensei used to give Yumi is?
Maya did mention sometime that current Sensei is simliar to past Sensei (which is also how he is remembered, but that might just be reset magic making people adapt).
Perhaps Pre-Loop Sensei and Player Sensei are one and the same. We, both the players and Sensei, just don't know it yet.
Not a great lore-buff, but I can (hopefully correctly) tell you that we have no idea.
The detentions are unknown. We've theorized that they could have been sexual, but there's no definitive proof for or against said argument.