But it is already like that.
You can play the game without doing anything naughty or romancing anyone. Or just one person. There's no penalty for going after couple of people either. Sometimes there are even additional dialogues if you are having hearts with more than one person (Logan may act differently, if you have heart with Bernard. Rhot can be jealous of Roushk if you have hearts with both of them).
You can play it however you want. At least that's what I'm trying to achieve.