I think Millie has always been in love with Theo. Because in the third chapter the mangaka states that the situation has been repeating itself since their high-school lives. Which means that Theo always thinks he's dreaming (having delusions) about Millie saying he's in love with him, and them having sex. However, in reality Millie is in love with Theo but he just never corrects him because Theo doesn't believe it to be true himself.
No. Because when Theo says that is because Millie was in love with the seme from the first story. In no moment we have some reassurance on Millie returning Theo's feelings. We can dream on Millie being as he is, he wouldn't have give in on Theo so easily so maybe there's some hope. But it can also be just a rebound fling. That's why I'm in desperate need of a proper ending
I need a little bit more assurance on the Millie/Theo couple... Pretty please???