There are four* mutually exclusive endings: Melody, Amy, Rebecca, and Isabella. The walkthrough mod will indicate when you need to choose between them.
Additionally, there are some scenes with Melody that are only available if you're not pursuing any of other women, but this mod will not automatically set you up for them. Like
belkak210 said, just set the other characters to disabled in the walkthrough settings and it should highlight the choices that
don't lead you to their relationships.
* Five, if you count the Bethany "bad ending"