There is zero requirement for your MC to have sex during the story if you don't want them to. Equally, if you want your MC to have sex but you as a player don't feel comfortable with sexual content then there are always multiple fade to black options during sex scenes.
While I hope that every completed route will be able to reach a satisfying conclusion regardless of whether MC has sex with their RO of choice, I'm hesitant to say for certain that both MC and their RO would definitely be in love. For some routes it is certainly that simple, but due to the short time frame of the story it may not be quite such a neat resolution for all (i.e. a happy ending for some characters may not be as much "definitely in love" as "will reluctantly acknowledge the presence of some feelings" hahaha).
I hope that makes sense? I've tried to be as specific as I can be without too many spoilers haha!