I know why

Do you know what it's like to just completely give in?
To say, 'What the fuck', and just let him in?
Do you know how useless you feel after that?
Like, on self respect, pride and dignity, you turned your back.
You look into his eyes, and you hear his voice,
And you think, "Why the fuck did I believe your lies?"
You look back in time, and you think really hard,
But, you can't fathom why you let him be back in your heart.
Fine, he didn't cheat, but what he did was no better,
You think of that fact while you hear his laughter,
He's trying to be funny, ten jokes in a row,
But, all you want, is him six feet below.
You can't understand what he'd have to have said,
To get so well right back into your head.
What he could've done, to make up for what he did,
And, yet, what lies he told, and all that he hid.
All you'd ever wanted, was a little bit of truth, 
But that's more than you can expect from his type of uncouth,
He lays beside you now, and you wonder,
"Was I right in forgiving him? Or was that another blunder?"
You look at him once, from up to down,
And in an instance, the smile turns into a frown,
For in that moment you realise,
The precise reason, exactly why,
You'd let him back inside,
And let him take you for a ride.
Again you look at him, from down to top,
And notice how he never seems to flop,
And then you think how much you'd just cried,
Out with pleasure, and how hard you'd sighed,
You think of how much a better a lover he is,
Than any of the guys you'd gotten with.
You realise the thrill of him inside of you,
Was enough to erase every fucked up thing he'd done to you.
You wonder when your body had taken over your mind,
When you'd begun to care more for what got in from behind,
Rather than what was said to your face,
Just so you'd have that last passionate embrace.