I think she has, but I'm inclined to be a bit more sympathetic, because Ginty hasn't withdrawn or switched her affections, where Patrick has. I think there's a fair bit of unexamined entitlement in Ginty's attitude: she feels that she's the natural object for Patrick's attention because they're closer in age, they shared enthusiasm for the Gondal and she's the Pretty One, and when her conscience troubles her about Nicola she quells it by thinking that a sort of Natural Order has been restored.