<human>: I was in a happy 3 year relationship with my girlfriend, when about a month ago she introduces me to one of her friends who we will call Amy.

Amy and I instantly connected, we share the same humour, tastes, hates and everything else you could imagine. I soon realised I was head over heels for this girl. We are in the same circles so I see her every weekend at various parties and every time I find my self spending more time with her than my girlfriend.

The thing is, If I break up with my girlfriend, I don't think I will ever see or talk to Amy again. That whole group is my girlfriends, and Amy would be shunned if she saw me again. I am so lost and for weeks I've been getting no sleep thinking about her and what to do.

I don't even know if Amy would want to go out with me, she would lose friends and has never been in a relationship before. There are just so many confusing factors!

I am not in my current relationship and I feel it is unfair to my girlfriend to continue it, but if I end it I lose the opportunity to see Amy as well as many friends I've made along the way in the course of our 3 year relationship.
Please help Reddit, I'm so lost.

Summarize the given text in a few sentences.
<bot>: My girlfriend and I [18] have been in a 3 year relationship and now I've fallen head over heels for her best friend