
hi! i just checked and he gains them back around chapter 76 https://darkstartranslations.com/manga/sencha-replica/c76/

sure ^^ extremely detailed summary below bc im a sucker for this novel and i yap alot lmao
to answer your questions 1) i cant exactly say there's a third wheel? as in he's really not all that threatening to the relationship between mc and ml in ANY way so there's rly no need to be worried! ill touch on this more in the spoilers
2) they sort of do break up id say since ml does go back to his normal aloof self when he gets his memories back (novel ch76-77) it feels extremely one sided though since ml doesn't remember the month he spent with mc as his 20 year old self but ml literally did everything so mc would fall in love with him within the month and even promised not to forget after he got his memories back but he forgot everything so.. mc was def extremely heartbroken when he started acting distant and i cried alot lol
summary: i cant really summarize fully the relationship between 20yo ml and mc bc when i switched to the novel i immediately skipped to the part where ml got his memories back but basically
[20yo ml chronicles] the whole time mc is really adamant on turning ml down but soon enough he folds bc he's a sucker for ml so the two of them do this thing where theyd record bits and pieces of ml being affectionate (+ sex) with mc as like insurance just incase ml forgets about mc (which he promises not to.. the boys a LIAR)
the day before ml leaves to get his memories back he makes mc breakfast and leaves a little note, mc decides to keep the leftover food + the note in the fridge since his mother once told him smth along the lines of "the fridge always makes time stop" as a sort of sentimental act? as in he wants what he has with 20yo ml at the moment to never end
[28yo ml chronicles] anyway so ml goes through training wtv to get his memories back its a whole thing right so when he gets them back mc finds out he imprinted with ml
tldr; imprinting is like mating in guideverse terms 1) both parties have to be in love + have real good sex idfk when it happens 2) you CANNOT break it unless one party finds someone else to imprint with or one party dies, also the imprinted esper won't be able to receive guiding from anyone else but their imprinted guide but the guide is just fine lmao
so mc is scared fucking SHITLESS as he thinks ml is gonna kill him to break the imprint, avoids him any chance he gets ANYWAY they're forced to meet for some sort of doctor's appointment and mc thinks ml's gonna beat his ass but all he does is talk to ml and apologizes since he thinks 20yo him came onto mc without permission
this is getting embarrassingly long so the gist of it is basically (forgive me if the order is wrong i forgot) -> mc tells ml he's gonna imprint with the s class esper assigned to busan (the third wheel i was talking about) -> ml is like damn ok go ahead
-> remember the tidbit about the note? right so mc and ml pack up their things in their old house, ml crumples up the note bc he didnt know it was important to mc and mc who's been holding his feelings in the whole time blows up and is fucking devastated, ml comforts him -> mc leaves for busan -> ml follows his ass to busan bc he's obsessed -> ml keeps using any excuse to hang out with mc -> mc keeps trying to meet up with the s class busan esper but ml doesnt let him -> they fuck and shit and that's basically all they do for the rest of the novel they fuck and they hang out with eachother (fin)
i started the novel and its so fucking funny n adorable im HOOOKED i honestly thought ml was too much when he was 20yo but 28yo ml when he turned back.. ADORABLE he's literally a big baby
novel link https://darkstartranslations.com/manga/sencha-replica/c1/