I did in one of the past chapters but in short(i used Google lens on Japanese raws, so I can't say is 100% accurate)
it was all a plan from the annoying couple that had a problem with Female lead, the Boyfriend gave some sleeping pills or something to the second girl(not Female lead), and the girl used the pills on MC and Female lead, assaulted MC, and let the alcohol cans to frame everyone, the plan was to tie MC with the pregnancy, there is plot with the teacher finding the sleeping pills pack in the trash and that helping MC somehow, MC confront the second girl, tells her that since he was drugged what she did was assault, and he have no intention of forming a family with her, he also say something like "think about how a kid would feel being born only to trap someone", she tries to cancel her life subscription, but Female lead stop her, MC find the Boyfriend who starts to talk shit, MC talks even bigger shit, Boyfriend gets mad and punch MC, Female lead got that on video, police is called Boyfriend is taken while girlfriend watches, I skipped some stuff so I don't know if the pregnancy was real or not, but, MC and Female lead have sex, time skip, the 2 got married