Each LI will have their own storylines and endings. Pregnancy is planned in a couple of ways. There will be a chance for LI to get pregnant, but given the amount of time that will elapse during your journey they would only be in the early stages of pregnancy during the main game. I am adding random encounters to the game and some of these will have a one night stand type content. I have one planned for a woman who is very far along in her pregnancy.