Not a milf tho, she's still young GF, TLDR MC is paranoid and sets up a lot of cameras, goes on a 3 week trip training camp and during that time a senpai comes to her house, drugs and rapes MH, breaks her and in the bad ending she still sleeps with senpai, MC knows all of this as this was recorded, preganant of another man, he plays dumb. Brutal route because she sends love filled texts and photos as she simultaneously cheats on MC, we can see side by side what happens with MC's cameras.
Good ending which is tricky to get MC decides to believe in her, sets no camera at all and when senpai comes she resists, fights back and he gets arrested. 3 weeks of peace and they get engaged once he comes back.