<human>: The two 19/f are also friends and I feel like I never should have gotten close to the 2nd one. For starters, let's name the first 19/f, the one I'm currently dating, Brittany and her friend, Susan. Brittany and I started going out last year (September 2013) after what seemed to be like a magical match. We had a lot of things in common and shared a lot of interests. After the honeymoon phase ended though, things started to get rocky and we're just now recovering from it. 

During that small rocky period though, Susan and I started hanging out and it was the honeymoon phase all over again. Spending time with Susan just seems a lot better, easier, and more fun than spending time with Brittany. While Brittany and I do have a small history together, I've known them for about the same amount of time.

Every time I think about spending time with Susan instead of Brittany, I feel like a cheating asshole but at the same time I don't want to keep Brittany in a relationship that might ultimately fail.

Can you condense the text into a few key points?
<bot>: Two 19/f are friends, Brittany (I'm dating) and Susan (just a friend). Starting to develop feelings for Susan. Feeling like an asshole.