At this point, I no longer know if Senpai actually even still love the past MC, since she literally letting a stranger (they might know each other name, but that pretty much about it, and future MC has a fake name at that) do lewd things to her every single time they meet, but oh well, might as well read and see the ending if its indeed just a hentai series or actually has plot.
Oh clearly she doesn't love the past MC anymore, this is a glorified Hentai series at this point with no deeper plot/meaning at all. A stranger did the cringy hentai-mindbreak on her, and apart from 2 glances at past MC, senpai shows no real connection to her apart from being acquaintances. Just shut brain off and enjoy the enjoyable spicy scenes, it's all this manga has to it since the writing is terrible.
I think I'll just take your advice cause the more I read this with my brain on the more I want to drop this