"We'll take this feeling to our graves, for every heart we betrayed.
No one can know about this"
This guy had a 'thing' with a girl while he was in a relationship but he knew it was wrong
so he's like 'woah calm down this can't get out'
"I know we're so wrong, but it feels so right"
He knows this 'thing' that him and the 2nd girl is wrong even though it feels right
"And it's not a party if it happens every night"
They happen to do things like have sex every night
but he can't use the excuse of 'oh i was at a party, it was a one time thing'
because it's happening every night
"We'll take this feeling to our graves, for every heart we betrayed. No one can know about this" This guy had a 'thing' with a girl while he was in a relationship but he knew it was wrong so he's like 'woah calm down this can't get out'
"I know we're so wrong, but it feels so right" He knows this 'thing' that him and the 2nd girl is wrong even though it feels right
"And it's not a party if it happens every night" They happen to do things like have sex every night but he can't use the excuse of 'oh i was at a party, it was a one time thing' because it's happening every night
just some of my interpretation