PROTIP: Coming inside a girl who said not to is a massive Affection penalty. If a girl says don't do it, don't. They'll tell you when it's okay. (Sub-Protip: Read the text/dialogues, don't just fast-forward through them.)How can I get Alice to have sex with me again, I already came inside her?
I assume this was when you first got her a key, yes? Or at least before Johan showed up? You need to rebuild her Affection. Buy drinks at the Inn and don't grab her ass when she brings them, and give her flowers (once a day only). If it's past that point and her Affection is good, but she hasn't gone to the Temple yet, she just might not be horny that day.