That is because she won't let you fuck her unless you have Condoms OR Plan B....I can see the misunderstanding here. I don't mean its impossible to cum inside her I just dont have the option to even fuck her and thats not because my score is too low.
You have to have one or the other or fucking is not an available option.
If all you have is condoms then she will fuck you but no creampie....
If you have Plan B you get all the options that are available in any given scene.
It is good to keep at least one of everything in your inventory.