<human>: Can you provide a brief rundown of the text in within 3 sentences?

My gf[22f] and I[23m] have been together for almost a year now. She basically moved into my house when we started seeing each other as well. However, I have started falling for another girl I used to work with and still see on an almost daily basis. I don't want to hurt my gf, but I know the relationship has to end. I'm not putting everything I have into it anymore and I don't feel for her like I used to, but I can't bring myself to hurt her like that. I need some advice, the stress of the situation is unbearable and I'm constantly feeling like a complete asshole for what I'm doing/not doing.
<bot>: I'm not cheating on my gf, physically at least. I'm just not into the relationship anymore but don't have the courage to do what has to be done...