I agree the game isn't going to be punitive, but it's possible to burn bridges with almost all the side girls if you play your cards right (or wrong, depending on how you look at it). If you never respond to Fiona, ignore Hank and don't hook up with Erica, tell Linda to get back with her husband, ask Tara to stop helping you with Jaye, stonewall Lisa, and find Tanaka's parlor trick unimpressive, I don't see any of them showing up in the MC's sunset. I'm not sure about Bianca, maybe she's being kept in play as the fallback?