I don't like the word "forced", but yeah there are canon events that cannot be avoided. We know that this can be unpopular, but the simple fact is that we're too inexperienced to juggle the development of purely optional sex scenes while still telling the story that we want to tell. We really, really, don't want to get into a position where development becomes a burden of juggling 100 different possible routes. But we also have a story that we want to tell, and that requires certain events to happen.
As a compromise, we try to give the player more influence over how the sex scenes play out. Players will either get the explicit choice about how the sex scene will proceed (not if it will proceed), or the scene will proceed based on prior choices made.
We aren't opposed to optional sex scenes that the player can opt-out of, and maybe down the road we'll get more comfortable with the development process where we can manage it. But for now we're trying to reign in our ambition and provide a fun game without needing a year to develop each episode.