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

So this girl at work is really cool, pretty, funny and full of life. Also I think she is very interested in me. We flirt a little, but nothing is clearly said. We exchange youtube music videos (we have the exact same taste in music, that's cool too) on facebook, yada yada I like her a lot. This situation has been going on for approximately one month now.

However I do have a girlfriend, in fact we have been living together for 10 months. She is in love with me. I don't think I'm in love with her, but I tell her "me too" when she says she loves me. (how sad is that?)

Nevertheless this girl that I'm with is really fun and I like her a lot too. She is my second relationship, first serious relationship. We go clubbing together, we do drugs together. Sex is great but has been a little less great lately. Overall I like my current situation A LOT.

Important information: the beginning of our relationship was really unstable, and she cheated on me while I was away for a week (3 months after we were serious). With a good friend nonetheless! I don't really think about it, but when I think about it (like now), it STILL bothers me, 7 months later. But she is forgiven. And she has changed since then and she loves me.

Should I break up with my girlfriend? How do I do that without destroying her heart? Am I engaging in self-destructing behavior?

Am I too scared of change or is that normal and I should stay with my girlfriend? Fuck, what do I do, I don't want to make her sad.

So many questions. Am I a coward? More importantly, am I a complete asshole towards my girlfriend?
<bot>: Really nice girl at work is seducing me. Do I break up with my girlfriend, who is in love with me?