I thought i knew!!!

When you love someone
you should let them go
if they come back then you know
i always thought that was true
but i was wrong i thought i knew
i let him go he came back
i thought i knew
that our love was true
all went well for a week or two
when i thought he wasn't true
true to me late one night
he wasn't true when i asked him who!
he said no one but then i knew
i knew that he had cheated
i knew that he had lied
i cried for 5 days and 5 nights!