Why do I lose love points and how can i stop it
Viewing post in Love & Sex : Second Base comments
You'll continue to lose love points more with the girl who you're trying to woo, when the people who she's associated with that are either her friends or someone she's jealous of. The more you talk to someone who is close to her, the more you lose, the only choice is to either end her or their rival's story first by putting them in the "friendzone." Also, by doing that ends their or her path permanently, so make sure to save before choosing a decision.
I've never experienced what the other person is saying, with certain plot exceptions, the girls don't seem to care what you are doing in regards to the other girls.
(Though kissing one girl in the same area where another girl you are romantic with will cause a negative hit to the other girl, and possibly set cheating flags).
However, if a girls lesbian stat is high they will lose a number of love points every day until you get their lesbian stat down low enough. (Typically done via advancing their story, though I believe there is a book that does it as well.)