Have a nice life

You say things to her,
like she's special, you love her, she's the only one.
But I know better,
you know better.
I've had a nice time,
with you.
But after all,
I can say you're ..
You cheated on her.
I had a nice summer,
did she?
I think she had too,
because she doesn't know what I know.
You know.
Have a nice life.