<human>: So The way that this all started was when she invited me to a latin dance because her friend wouldn't dance with her. he sat on the benches while she ruffled my hair and we danced and got REALLY close doing that. It wasn't until after the dance that i found out that was her boyfriend who wasn't dancing. 

She's always been really cute to me, and so i asked my friend about it. He and i have always had a close relationship and talk about stuff this personal to each other a lot. I asked him if it was okay and he said ''OP, no matter what decision you make, i'll be there for you''. She clearly wasn't that into her boyfriend anymore so i decided that i should make a move soon. 

The problem now is that my friend thought that his sister would NEVER like me. The reason he was supportive of me was because he thought i didn't have a chance. I know that what he did was a dick move, but i'm not sure if i want to compromise the friendship we have over something like this.

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: Friend's cute sister and i want to go out. Friend said it was okay because he thought i didn't have a chance. Now he's against it