What are we?

I lye awake thinking of you,
As you go out and party,
I wonder if you'll be alright,
Or if your thinking of me,
As i lye awake thinking of you,
I imagine things as if you were actually doing them,
I realize i am lucky to have you,
Whether I'm with you or not,
But even when I'm with you,
It seems like you see right through me,
What do you see in me?
You come and go,
We do our thing,
And we don't have strings attached,
But isn't that weird,
We aren't dating and we do things...
Things that maybe we shouldn't be doing ,
But yet we keep coming back to each other,
Even when you cheated on me,
Even when you left me for someone else for the second time...
But now we have nothing to worry about right?
When we come and go as we please and theres no strings attached,......
What are we?