Confirmed Bachelor means your character is homosixual. That's probably it.
this.
neither confirmed bachelor or lady killer-unknown
confirmed bachelor-gay
lady killer- straight
both-well...er...both ways
Let's not jump to confusions here. While in the US the term Confirmed Bachelor has in the past been used as a polite euphemism for a male homosixual, there is nothing in the seemingly carefully selected dialog of the Courier to indicate that he is, indeed, gay—although one is free to role play him in that manner.
The responses of certain NPCs, however are more clear cut.
All the perk does is make the Player Character more appealing to other male NPCs. Several nebulous responses like, "I don't know what it is, but I just like you," are indicative of this. The only blatant exception is Dr. Richards, whose comments and responses are patronizingly chauvinistic.
Since there is no male/male six in the game (discounting prosttutes) and the Confirmed Bachelor can still have a fling with Red Lucy, that leaves the only real same-six relations up to female Player Characters.