I am involved with a really nice girl. Been together for 6 months now, however I have feelings for her friend. And I was more interested in her friend the day I met them both, it just happened that I went with the current girl because the friend has a boyfriend. Now I feel like shit for being such an asshole to my girlfriend, I assumed it would be just casual dating, nothing serious. But today she told me she loved me. And I couldnt say the same to her,,, but I still did. What to do?